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The  Theory  and  Practice 


OF 


INFANT  FEEDING 

With  Notes  on  Development 


HENRY  DWIGHT  CHAPIN,  A.M.,  M.D. 

Professor  of  Diseases  of  Children  at  the  New  York  Post-Graduate  Medical 

School  and  Hospital ;   Attending  Physician  to  the  Post-Graduate, 

Willard    Parker   and   Riverside  Hospitals  ;  Consulting 

Physician  to  the  Randall's  Island  Hospital. 


WITH    NUMEROUS    ILLUSTRATIONS 


NEW    YORK 

WILLIAM  WOOD  AND  COMPANY 

MDCCCCII 


ft    - 


Copyright,  1902, 
By  WILLIAM   WOOD   AND   COMPANY 


Co  ntp 

FATHER  AND  MOTHER 

this    volume   is 

affectionately    dedicated 


PREFACE. 

THE  great  and  increasing  importance  the  subject  of 
artificial  infant  feeding  is  assuming  in  all  classes  of 
society  has  led  the  author  to  believe  there  might  be  a 
field  for  a  work  on  this  subject  that,  instead  of  laying 
down  rules  and  formulas  for  preparing  food  supposed  to 
be  suitable  for  infants  of  different  ages,  aimed  rather  to 
show  the  fundamental  principles  of  growth,  nutrition, 
and  digestion  during  infancy,  and  then  leave  it  to  the 
physician  to  apply  these  principles.  The  discovery  that 
the  law  of  conservation  of  energy  applies  to  animal  life 
has  made  the  nutrition  of  adults  almost  an  exact  science. 
In  infant  feeding  there  are  other  problems  than  mere 
nutrition  that  must  be  considered.  The  great  mass  of 
literature  on  infant  feeding  that  has  appeared  within  the 
past  few  years  has  been  devoted  in  the  most  part  toward 
producing  a  substitute  food  that  should  chemically  ap- 
proximate human  milk.  In  this  book  the  special  func- 
tion of  milk  in  developing  the  digestive  tract  of  the 
young  animal  is  treated,  the  author  believes,  for  the  first 
time,  and  it  is  more  than  likely  that  further  study  along 
this  line  may  necessitate  greater  or  less  modification  of 
the  conclusions  here  drawn. 


vi  PREFACE. 

American  authorities  on  milk  have  been  followed  be- 
cause the  conditions  under  which  milk  is  produced  and 
marketed  in  America  are  so  different  from  those  of  Europe 
that  many  statements  found  in  European  medical  jour- 
nals concerning  milk  supplies  must  be  inapplicable  to  the 
work  of  a  majority  of  American  physicians,  and  besides, 
the  greatest  advances  in  dairying  and  knowledge  of  the 
chemistry  of  milk  have  been  made  in  America. 

In  the  Appendix  will  be  found  a  list  of  works  and 
articles  from  which  data  have  been  drawn.  The  material 
of  the  book  has  been  divided  into  four  parts,  each  being 
as  complete  in  itself  as  the  subject  will  allow.  By  a 
system  of  cross  references  it  is  aimed  to  bring  the  prin- 
ciples involved  and  their  application  in  close  connection. 

The  author  wishes  to  acknowledge  his  indebtedness 
to  Profs.  W.  A.  Henry,  S.  M.  Babcock,  and  F.  W. 
Woll,  and  Major  H.  E.  Alvord  for  valuable  information; 
to  Professor  H.  W.  Conn  for  the  chapter  on  Bacterio- 
logical Examination  of  Milk;  to  Dr.  Hrdlika  for  making 
anthropological  measurements,  assisted  by  Dr.  Pisek,  and 
to  Dr.  Pisek  for  securing  the  photographs  of  infants. 
The  thanks  of  the  author  are  also  extended  to  th,e  pub- 
lishers for  courtesies  rendered  during  the  preparation  of 

the  volume. 

Henry  Dwight  Chapin. 

51  West  Fifty-First  Street,  New  York, 
August  1,  1902. 


CONTENTS. 


PART   I. 

UNDERLYING   PRINCIPLES    OF   NUTRITION. 

CHAPTER  I. 

I'AGE 

General  Introduction,         .         .         .         .  .         .         .         .         .       i 

CHAPTER  II. 
How  to  Approach  the  Subject  of  Infant  Feeding,  ....       6 

CHAPTER  III. 
Animal  Cell— Its   Constituents— Growth  a  Process  of  Cell  Division — 

Young  Animal  Rudiment  of  Parent,  ......     10 

CHAPTER  IV. 
Object  and  Processes  of  Digestion — Mechanism  and  Comparisons  of 
Digestive  Tracts, 16 

CHAPTER  V. 
Broad  Classification  of  Food  into  Protein,  Fat,  Carbohydrates,  Min- 
eral Matter,  and  Water,      .         .         ...         .         .         .         .         .25 

CHAPTER  VI. 
The   Chemical   Processes  of  Digestion — Comparative  Digestion  and 

Absorption  in  Different  Animals,       .         .         .         .         .  29 

CHAPTER  VII. 
Metabolism  and  Excretion,        .  ........     36 

CHAPTER  VIII. 
Comparison  of  the  Milk  of  Different  Animals.     Chemical  and  Physio- 
logical Differences,       ..........     43 

CHAPTER   IX. 
Summary,   .    •     .  ' 54 


viii  CONTENTS. 

PART    II. 

RAW   FOOD    MATERIALS. 

PAGE 

CHAPTER  X. 
Cow's  Milk, 59 

CHAPTER   XL 
Bacteriology  of  Milk, So 

CHAPTER  XII. 
Preservation  of  Milk,  ..........     94 

CHAPTER  XIII. 
Market  Milk, 104 

CHAPTER  XIV. 
Methods  of  Testing  Milk, 127 

CHAPTER  XV. 
Bacteriological  Examination  of  Milk,       .......   140 

CHAPTER  XVI. 
Cereals,  and  Vegetable  Foods,  ........   162 

CHAPTER  XVII. 
Proprietary  Infant  Foods,  .         .         .         .         .         .         .         .         .171 

CHAPTER  XVIII. 
Meats  and  Eggs. 175 


PART   III. 
PRACTICAL   FEEDING. 

CHAPTER  XIX. 
Breast  Feeding — Diet  and  Care  of  Mother — Elimination  of  Drugs  in 
Milk — Care  of  Nipples — Contraindications — Menstruation — Preg- 
nancy— Wet-Nursing — Weaning  and  Mixed  Feeding,     .         .         .   1S7 

CHAPTER  XX. 
Methods  of  Selecting  Food  for  Adults  not  Applicable  to  Infants— Nu- 
trition and  Development  of  the  Digestive  Tract  must  be  Consid- 
ered Together, 198 

CHAPTER  XXI. 
General  Considerations  in  Preparing  Infant's  Food,      ....  207 


CONTENTS.  ix 

PAGE 

CHAPTER  XXII. 
Preparation  of  Food,  ..........  227 

CHAPTER  XXIII. 
Selection  and  Administration  of  Food, 246 

CHAPTER  XXIV. 
Feeding  by  Gavage — Nasal  Feeding — Rectal  Feeding — Feeding  Pre- 
mature Infants,  ..........   258 

CHAPTER  XXV. 
Constipation,       ............  265 

CHAPTER  XXVI. 
Summer  Diarrhoea,    ...........   270 

CHAPTER  XXVII. 
Diet  During  Second  Year, 279 

PART   IV. 
GROWTH   AND   DEVELOPMENT   OF   INFANTS. 

CHAPTER  XXVIII. 
Growth  and  Development  of  Infants 287 

CHAPTER  XXIX. 
Methods  and  Results  of  Measuring  Normal  Infants,      ....  300 

CHAPTER  XXX. 
Growth  of  Head, 308 

References, 317 

Index, 521 


PART    I. 


CHAPTER    I. 

GENERAL    INTRODUCTION. 

Two  controlling  factors  are  present  in  all  life — hered- 
ity and  environment.  At  the  birth  of  the  individual  the 
first  has  done  its  best  or  worst  and  cannot  be  reckoned 
with  in  the  sense  of  being  influenced.  Its  activity  has 
been  through  long  reaches  of  past  time,  and  the  laws  of 
its  operation  are  but  imperfectly  understood.  The  ques- 
tion of  environment,  being  of  the  present  and  to  a  certain 
extent  possible  of  control,  assumes  the  greatest  impor- 
tance. While  from  a  purely  biologic  standpoint  heredity 
may  appear  to  be  the  most  important  influence,  yet  in  the 
scheme  of  evolution  the  higher  the  animal  the  more  im- 
portant becomes  environment.  This  is  specially  empha- 
sized in  man  by  the  prolongation  of  the  period  of  infancy. 
John  Fiske  was  the  first  to  elaborate  this  fruitful  view  of 
one  of  the  fundamental  laws  of  higher  evolution,  that  not 
only  throws  a  strong  light  on  the  methods  of  evolution, 
but  lays  the  greatest  importance  on  the  period  of  infancy 
as  influencing  the  future  development  and  usefulness  of 
the  animal.  This  long  period  of  helpless  infancy  is  a  time 
of  extreme  plasticity,  when  the  career  of  the  individual 
is  no  longer  predetermined  by  the  career  of  its  ancestor. 
One  generation  of  the  lower  animals  is  almost  an  exact 
reproduction  of  the  preceding  one.  The  young  animal  is 
born  pretty  fully  formed,  and  can  look  out  for  itself  almost 


2  INFANT    FEEDING. 

from  the  beginning,  independently  of  the  parent.  The 
longer  the  infancy  of  an  animal  becomes,  the  greater  the 
period  of  its  teachability,  and  a  slow  growth  means  an 
increase  in  capacity  for  development  and  all  the  higher 
prerogatives.  Thus  the  higher  apes  have  a  helpless  baby- 
hood, when  for  two  or  three  months  they  are  unable  to 
feed  themselves  or  move  about  independently  of  the  pa- 
rent. The  human  infant  is  distinguished  from  the  high- 
est of  the  lower  animals  by  the  very  long  duration  of  help- 
less infancy  and  the  marked  increase  in  the  size  of  the 
brain,  and  particularly  in  the  extent  of  its  surface. 
There  is  here  a  great  increase  in  the  size  and  complexity 
of  brain  organization  that  takes  place  largely  after  birth. 
Accompanying  the  rapid  growth  of  the  nervous  system 
is  that  of  the  skeleton  and  various  visceral  organs.  Dur- 
ing the  first  two  years  of  life  the  brain  not  only  doubles 
in  weight,  but  increases  marvellously  in  its  convolutions 
and  complexity.  The  infinite  distance  between  man  and 
the  lower  animals  consists  in  the  fact  that  in  the  former 
natural  selection  confines  itself  principally  to  the  surface 
of  the  brain,  and  requires  a  long  period  of  helpless  infancy 
for  this  highly  plastic  work  to  be  properly  started  and 
developed.  Inherited  tendencies  are  there,  but  the  proper 
environment  counts  for  much  in  this  work  so  potent  in 
future  possibilities.  It  is  evident  that,  correlated  with  his 
long  period  of  helpless  infancy,  there  must  be  a  time  of 
maternal  care  and  watchfulness,  if  the  race  is  to  exist  in 
health  and  vigor.  Knowledge  is  required  as  well  as  care, 
for  mistakes  made  at  this  time  can  never  be  completely 
corrected.  The  first  few  years  of  life  are,  biologically 
speaking,  the  most  important  ones  we  live.     The  begin- 


GENERAL    INTRODUCTION.  3 

ning  organism  has  at  this  time  stamped  on  it  the  possi- 
bilities of  future  vigorous  life  or  of  early  degeneration  and 
decay.  Hence  a  careful  study  and  understanding  of  all 
the  phases  of  infancy  are  of  the  greatest  importance  alike 
to  physicians  and  parents.  At  a  period  of  such  rapid 
growth  and  development,  it  is  evident  that  proper  nutri- 
tion must  play  the  leading  part.  All  competent  observers 
are  agreed  that  the  best  nourishment  for  a  baby  naturally 
comes  from  its  own  mother.  Unfortunately  a  large  num- 
ber of  mothers,  from  physical  or  social  causes,  are  unable 
to  give  this  proper  nutriment.  It  appears  to  be  one  of 
the  penalties  of  modern  civilization  that  an  increasing 
number  of  women  cannot  or  will  not  nurse  their  offspring. 
Hence  it  is  that  in  recent  years  a  large  amount  of  study 
and  labor  has  been  expended  upon  substitute  infant  feed- 
ing. Great  advances  have  been  made,  but  it  must  be 
confessed  that  the  results  are  not  always  proportionate  to 
the  labor  expended.  The  tendency  appears  to  be  to  a 
greater  degree  of  complexity  and  elaborateness  than  the 
average  practitioner  and  mother  can  understand  or  ap- 
ply. Hence  discouragement  is  apt  to  follow,  and  a  return 
to  old  and  haphazard  methods  if  the  immediate  results 
are  fairly  satisfactory.  Proprietary  infant  foods  also  pro- 
fit by  this  feeling  of  confusion,  as  they  often  agree  with 
the  baby  for  the  time  being,  although  not  containing  the 
proper  ingredients  for  healthy  growth  and  nutrition. 

The  effort  to  place  the  food  principles  of  milk  in  their 
proper  ratio  has  led  to  "percentage  feeding,"  which  rep- 
resents a  decided  advance,  but  has  been  pushed  to  an 
extreme  that  is  difficult,  if  not  impossible,  to  apply.  The 
author  has  long  thought  that  some  of  the  benefits  of  this 


4  INFANT   FEEDING. 

method  of  feeding  come  more  from  the  care  and  cleanli- 
ness with  which  the  milk  is  handled  than  from  the  minute 
changes  in  the  percentages  that  are  often  advised;  in- 
deed, analysis  sometimes  shows  that  these  fine  changes 
are  more  on  paper  than  in  the  ingredients  of  the  milk. 
It  is  well  to  think  in  percentages  and  be  as  exact  as  pos- 
sible in  feeding  a  baby,  but  the  problem  has  not  thus 
been  completely  solved,  when  we  are  putting  the  milk  of 
one  species  of  animal  into  the  stomach  of  another  spe- 
cies having  a  different  digestive  apparatus. 

The  greatest  problem  in  the  life  of  any  animal  is  that 
of  securing  sufficient  food.  All  forms  of  animal  life  de- 
mand the  same  ultimate  food  elements,  so  that  really 
their  great  diversification  is  along  the  lines  of  methods 
and  organs  provided  by  nature  for  securing  and  digesting 
food.  While  the  outward  forms  of  animals  are  apparent 
to  every  casual  observer,  their  digestive  systems,  which 
are  hidden,  are  as  much  diversified  as  their  more  appar- 
ent shapes,  and  are  as  much  adapted  for  the  digestion  of 
a  particular  food  as  the  outward  organs  are  for  securing 
it.  Hence  the  milk  of  each  type  of  animal  must  be  stud- 
ied from  the  standpoint  of  its  special  adaptation  to  the 
digestive  tract  for  which  it  is  intended :  a  hard  curding 
milk  is  intended  for  a  polygastric  digestive  tract  that  can 
properly  deal  with  it ;  a  soft  curding  milk  for  a  monogas- 
tric  digestive  tract.  These  differences  assume  the  great- 
est importance  when  the  milk  of  one  species  of  animal  is 
fed  to  another  species.  This  subject  will  be  carefully 
considered  in  the  present  work,  as  it  has  a  direct  practical 
bearing  upon  successful  infant  feeding.  While  percen- 
tage feeding  and   the  physical  differences   in   the  same 


GENERAL   INTRODUCTION.  5 

ingredients  in  the  milks  of  different  species  are  of  great 
importance,  the  preliminary  question  of  how  to  get  clean, 
fresh  cow's  milk  is  the  fundamental  one.  Too  little  atten- 
tion has  been  given  to  this  question  in  works  on  infant 
feeding.  It  will  here  be  treated  at  some  length  and  in 
detail,  as  the  observations  of  the  author  lead  him  to  be- 
lieve that  future  advances  in  infant  feeding  must  be  prin- 
cipally along  this  line.  In  order  to  insist  upon  pure,  clean 
milk,  the  physician  must  know  how  it  is  produced  and 
insist  upon  proper  conditions.  It  can  easily  be  produced 
anywhere,  if  the  details  are  properly  carried  out ;  and  this 
does  not  require  an  elaborate,  expensive  plant,  as  many 
believe.  It  calls  for  knowledge  on  the  part  of  the  physi- 
cian or  sanitarian  that  can  easily  be  conveyed  to  the  farmer 
and  dairyman.  This  is  the  first  requisite  in  successful 
infant  feeding. 


CHAPTER    II. 

HOW  TO   APPROACH   THE  SUBJECT  OF 
INFANT   FEEDING. 

i.  Any  one  called  on  to  feed  an  infant  during  the  period 
it  is  normally  nourished  by  its  mother  has  a  great  respon- 
sibility thrust  upon  him  and  one  not  to  be  assumed  lightly 
or  without  preparation.  Too  many  are  satisfied  when 
something  that  is  retained  in  the  stomach  and  causes  a 
gain  in  weight  is  found,  no  thought  being  given  to  whether 
the  food  contains  material  out  of  which  healthy  tissue  can 
be  formed. 

It  has  often  been  stated  that  an  artificial  food  for  in- 
fants should  contain  nothing  that  is  not  found  in  mother's 
milk,  and  that  it  should  contain  just  what  is  found  in 
mother's  milk.  To  prove  the  suitability  of  various  substi- 
tutes for  mother's  milk  chemical  analyses  of  both  have 
been  published,  to  show  how  closely  the  substitutes  ap- 
proximate mother's  milk.  At  first  sight  this  seems  a  ra- 
tional procedure,  but  when  it  is  remembered  that  there  is 
no  difference  between  a  diamond  and  a  piece  of  charcoal 
chemically ,  and  that  mixtures  of  butter,  cheese,  sugar, 
salts,  and  water,  or  of  beef  suet,  raw  beef,  sugar,  salts, 
and  water,  can  be  made  which  when  analyzed  by  the  usual 
methods  will  show  the  same  composition  as  mother's 
milk,  the  fallacy  of  judging  the  suitability  of  a  food  for  an 
infant,  or  for  an  adult  for  that  matter,  by  its  chemical 


HOW  TO   APPROACH    INFANT    FEEDING.         7 

analysis  only  will  be  apparent.  Physiological  chemistry 
has  not  advanced  sufficiently  to  make  it  a  safe  guide  by 
itself. 

In  feeding  an  adult  it  is  only  necessary  to  furnish 
enough  food  to  repair  waste.  In  feeding  an  infant  not 
only  must  waste  be  repaired,  but  material  to  build  up  new 
tissue  must  be  supplied,  or  the  infant  cannot  grow  nor- 
mally. The  whole  future  of  the  infant  may  depend  on 
what  kind  of  food  is  supplied  it  up  to  the  time  it  can  take 
table  food.  Then  the  danger  of  an  insufficient  supply  of 
tissue-building  food  is  not  so  great. 

The  ability  to  resist  disease  depends  largely  on  having 
the  cells  in  which  the  vital  processes  take  place  plentiful 
in  number  and  well  nourished.  These  cells  form  a  large 
portion  of  all  the  organs  and  tissues  of  the  body,  and  if 
the  material  needed  to  build  cells  is  not  furnished  in  suffi- 
cient quantity,  the  gain  in  weight,  if  there  is  any,  will  be 
mostly  fat  and  water.  It  does  not  follow  that  because  a 
baby  is  fat  that  it  is  strong  or  healthy.  The  cells  may  be 
actually  starving  and  so  few  in  number  that  the  body  may 
be  likened  to  a  large  showy  house  built  with  very  light 
timbers,  all  ready  to  collapse  under  a  slight  strain   (128). 

Not  only  must  the  food  for  an  infant  contain  material 
from  which  cells  may  be  built  up,  but  the  material  must 
be  in  such  a  condition  that  the  infant  can  digest  it  with- 
out undue  effort.  Furthermore  the  food  must  be  cheap 
enough  to  be  within  the  reach  of  all  and  easily  prepared. 

Naturally  the  milk  of  the  cow  or  of  some  other  animal 
is  suggested,  but  experience  shows  that  these  milks  do 
not  agree  with  infants  generally,  unless  in  some  way 
changed  or  modified,  the  great  difficulty  being  the  inabil- 


8  INFANT   FEEDING. 

ity  of  the  infant  to  digest  the  elements  of  the  milk  of 
which  cells  are  composed.  Undoubtedly  the  milk  of  all 
animals  contains  the  materials  necessary  to  build  up 
strong  healthy  cells  and  tissues,  as  no  young  animal 
thrives  as  well  on  anything  else  as  it  does  on  its  mother's 
milk  or  on  the  milk  of  some  other  animal  of  the  same 
species.  At  first  thought  it  seems  strange  that  the  milk 
of  one  species  of  animal  is  not  suitable  for  the  young  of 
another  species ;  but  when  the  mode  of  living,  and  the 
digestive  systems,  rate  of  growth,  and  stage  of  develop- 
ment at  birth  of  the  different  species  are  compared,  it  will 
be  found  that  the  milk  of  each  animal  is  adapted  to  its  own 
digestive  system,  rate  of  growth,  and  state  of  development ; 
also  that  the  milk  of  the  mother  behaves  in  the  young  ani- 
mals stomach  very  much  as  the  food  of  the  mother  behaves 
in  her  stomach.  The  young  animal  is  being  educated  to 
digest  in  the  same  manner  as  it  will  when  it  is  grown. 
This  subject  will  be  gone  into  in  detail  in  subsequent 
chapters,  as  it  has  been  given  very  little  or  no  considera- 
tion by  writers  on  infant  dietetics. 

Before  there  can  be  intelligent  food  prescribing  there 
must  be  a  knowledge  of  the  substances  needed  to  con- 
struct cells  and  keep  them  well  nourished ;  of  the  sources 
from  which  these  substances  may  be  obtained;  of  how 
they  are  transmitted  to  the  cells  through  the  blood  stream 
after  digestion  and  absorption ;  of  the  nature  of  digestion 
and  the  digestive  systems  of  different  animals ;  of  what 
changes  take  place  in  the  food  in  the  cells,  and  what  be- 
comes of  the  waste  products.  Then  only  can  feeding  be 
taken  up  in  a  scientific  manner. 

The  problem  of  feeding  infants  in  all  classes  of  society 


HOW  TO   APPROACH    INFANT   FEEDING.         9 

calls  for  ability  to  produce  a  satisfactory  food  in  a  simple 
and  inexpensive  manner.  This  necessitates  a  knowledge 
of  raw  food  materials,  how  they  are  produced,  and  the 
best  means  of  preserving  them  from  deterioration  and  in- 
fection by  disease  or  other  kinds  of  germs,  and  how  these 
food  materials,  no  matter  what  their  source,  may  be  best 
prepared  for  digestion  by  the  infant. 

Before  taking  up  methods  of  preparing  food  for  in- 
fants, some  space  will  be  devoted  to  physiological  chem- 
istry, physiology  of  young  animals,  comparison  of  the 
digestive  systems  and  milks  of  various  animals,  the  produc- 
tion of  milk  and  other  raw  food  products,  and  methods 
of  analyzing  and  testing  food  materials. 


CHAPTER    III. 

ANIMAL  CELL— ITS  CONSTITUENTS— GROWTH 
A  PROCESS  OF  CELL  DIVISION— YOUNG 
ANIMAL  RUDIMENT   OF   PARENT. 

2.  The  unit  of  the  animal  organism  is  the  cell.  In  the 
cells  all  the  vital  processes  take  place.  They  are  the 
chemical  laboratories  of  the  body  and  are  the  ultimate 
destination  of  all  the  food  that  is  digested. 

The  starting-point  in  the  growth  of  an  animal  is  a  sin- 
gle cell  about  one-one-hundred-and-twenty-fifth  of  an  inch 
in  diameter.  This  cell  divides  and  forms  an  additional 
cell;  these  divide  again,  and  so  on.  After  a  large  number 
of  cells  have  been  thus  formed,  they  arrange  themselves 
into  a  membrane — the  blastoderm — which  consists  of  two 
distinct  portions:  (i)  The  archiblast,  which  consist  of 
three  layers — (a)  the  epiblast  or  outer  layer,  (5)  the  meso- 
blast  or  middle  layer,  and  (c)  the  hypoblast  or  inner  layer; 
and  (2)  the  parablast,  which  fills  up  the  spaces  in  the  meso- 
blast  or  middle  layer. 

As  the  process  of  cell  division  proceeds,  the  epiblast 
or  outer  layer  develops  into  the  skin  and  nervous  system, 
the  mesoblast  or  middle  layer  into  the  muscles,  and  the 
hypoblast  into  the  lining  of  the  respiratory,  genito-uri- 
nary,  and  digestive  systems ;  while  the  parablast,  which 
filled  up  the  spaces  in  the  mesoblast  or  middle  layer,  be- 
comes connective  tissue,  cartilage,  bone,  lymphatic  ves- 
sels and  tissues,  blood  cells,  and  blood-vessels. 


ANIMAL   CELL. 


ii 


When  the  animal  is  able  to  maintain  a  separate  exis- 
tence it  is  born,  and  to  become  an  adult  it  has  simply  to 
enlarge  and  develop  all  the  parts  and  add  mineral  matter 


Fig.  i. — Section  of  Ovum.     (Jewett.)     Shows  the  original  cell  or  starting-point  of  an  animal. 

to  the  bones.     This  enlarging  and  developing  of  the  body, 
or  growing,  is  a  simple  extension  of  the  process  of  cell 

ZONA 
PELLUCIDA 


POLAR 
GLOBULES 


Fig.  2.— Illustration  of  Cell  Division  or  Growth.     (Allen  Thompson,  after  E.  Van  Beneden.) 

division.  There  can  be  no  true  growth  without  an  in- 
crease of  the  number  of  cells,  and  no  new  cells  can  be 
formed  except  by  the  division  of  old  cells. 


12  INFANT   FEEDING. 

The  cells  are  so  small  that  they  cannot  be  examined 
except  by  the  aid  of  a  microscope,  but  as  they  make  up 
a  large  part  of  the  tissues  of  the  body,  a  study  of  the  tis- 
sues is  practically  a  study  of  the  cells. 

To  the  eye  a  piece  of  flesh  consists  of  muscle,  connec- 
tive tissue,  cartilage,  fat,  and  possibly  mucous  membrane, 
skin,  blood-vessels,  and  nerves. 

The  chief  mass  of  these  tissues,  with  the  exception 
of  water  and  fat,  is  called  protein  substance — the  word  pro- 
tein meaning  "/  take  the  first  place!'  All  protein  sub- 
stance contains  carbon,  hydrogen,  oxygen,  and  nitrogen. 
Mostoi  it  contains  in  addition  sulphur,  and  portions  con- 
tain also  phosphorus  and  iron.  While  the  quantities  of 
these  elements  vary  somewhat,  they  are  fairly  constant  in 
all  of  the  tissues,  but  a  chemical  analysis  of  protein  would 
not  tell  whether  it  came  from  skin,  mucous  membrane,  or 
muscle.  Other  means  of  examining  tissues  had  to  be 
devised.  These  consist  of  extracting  the  tissues  with 
various  solvents.  By  this  process  various  forms  of  pro- 
tein can  be  separated  to  a  certain  extent.  The  principal 
groups  of  protein  substances  so  separated  are: 

(i)  Albumins  and  globulins,  containing  carbon,  hy- 
drogen, oxygen,  nitrogen,  and  sulphur. 

(2)  Nucleo-albumins,  containing  carbon,  hydrogen, 
nitrogen,  oxygen,  sulphur,  and  also  phosphorus  and  iron. 

There  are  many  forms  of  protein  that  are  included  in 
these  divisions;  for  instance: 

White  of  egg  is  a  mixture  of  albumin  and  globulin. 

Casein  of  milk  (curd)  is  a  nucleo-albumin. 

Another  class  of  substances  which  contain  carbon^ 
hydrogen,  oxygen,  and  nitrogen,  but  which  are  not  protein 


ANIMAL   CELL.  13 

substances,  can  be  separated  from  animal  tissues.  These 
are  called  extractives  or  meat  bases.  The  extracts  of  meat 
for  making  beef  teas,  sold  in  jars,  which  are  claimed  to 
represent  ten  to  twenty  times  their  weight  "of  meat,  are 
"extractives  "  (no). 

Fat,  which  is  composed  of  carbon,  hydrogen,  and  oxy- 
gen only ;  lecithin,  a  kind  of  fat  which  contains  also  phos- 
phorus and  nitrogen,  found  particularly  in  the  brain  and 
nerves;  and  glycogen  or  animal  starch,  composed  of  car- 
bon, hydrogen,  and  oxygen,  but  in  proportions  different 
from  those  in  fat,  can  also  be  separated  from  animal  tissues. 

Mineral  substances  found  in  the  tissues  are  thought  to 
be  combined  with  the  protein  substances  and  not  to  exist 
in  a  free  state. 

3.  In  examining  cells  under  a  microscope,  it  is  found 
that  a  certain  portion  of  each  cell — the  nucleus — contains 
iron  and  phosphorus,  and  that  the  albumins  and  globulins 
which  do  not  contain  iron  and  phosphorus  serve  more  as 
cell  food  than  as  cell  builders.  Lecithin  and  glycogen 
seem  to  be  found  in  all  cells. 

There  can  be  no  cell  division  or  growth  unless  the 
nucleus  of  the  cell  first  divides,  and,  as  iron  and  phospho- 
rus are  contituents  of  the  nuclei  of  cells,  there  can  be 
no  cell  growth  unless  food  containing  iron  and  phospho- 
rus is  furnished.     This  has  been  proved  by  experiment. 

The  materials  necessary  to  build  up  cells  must  be 
found  in  eggs,  as  in  an  egg  there  is  a  single  cell  that  be- 
gins to  divide  and  ends  by  changing  the  contents  of  the 
shell  into  a  live  bird.  The  germinal  cell  is  situated  near 
the  yolk,  which  is  used  up  first,  and  then  the  white  is 
drawn  on.     The  yolk  is  rich  in  protein  containing  phos- 


i4  INFANT   FEEDING. 

phoms  and  iron,  lecithin,  fat,  and  mineral  matter;  while 
the  white  of  the  egg,  which  is  about  eighty-five  per  cent 
water,  contains  almost  nothing  that  could  be  used  to  cre- 
ate cells  (2). 

4.  Up  to  the  time  an  animal  is  born  it  is  nourished  by 
the  blood  stream  of  its  mother,  so  all  the  elements  for  the 
developing  animal  must  come  originally  from  the  moth- 
er's food.  It  would  be  expected  that  animals  that  feed 
on  flesh,  as  cats  and  dogs,  would  be  able  to  supply  the 
materials  needed  to  construct  animal  tissue ;  but  animals 
that  feed  exclusively  on  vegetable  substances,  as  cows, 
sheep,  and  horses,  also  have  no  difficulty  in  constructing 
animal  tissue.  In  fact,  most  of  the  meat  supply  of  the 
world  is  the  flesh  of  animals  that  live  exclusively  on  vege- 
table substances,  so  the  only  conclusion  is  that  the  vege- 
table kingdom  must  be  able  to  supply  all  the  materials 
necessary  to  form  animal  tissue. 

Examination  of  hay,  wheat,  oats,  barley,  corn,  beans, 
etc..  shows  them  to  consist  principally  of  carbohydrates 
which  contain  only  carbon,  hydrogen,  and  oxygen.  Cel- 
lulose, or  the  skeleton  of  plants,  starch,  and  sugar  are 
typical  carbohydrates.  Paper  is  made  of  the  cellulose  or 
cells  of  wood  or  straw.  Potatoes  and  cereals  contain  large 
quantities  of  starch,  and  beets,  sugar  cane,  and  maple 
trees  supply  sugars.  Starch  and  sugar  are  the  stored-up 
food  of  plants.  Vegetable  tissues  contain  also  small 
quantities  of  fat  and  lecithin  and  substances  containing 
carbon,  hydrogen,  oxygen,  nitrogen,  and  also  sulphur, 
phosphorus,  and  iron,  called  vegetable  protein.  It  is  these 
substances  that  are  converted  into  animal  cells.  Gluten 
or  the  sticky,  stringy  part  of  bread  dough  is  a  familiar 


ANIMAL   CELL.  15 

form  of  vegetable  protein.     Chemically  there  is  little  dif- 
ference between  gluten  and  lean  meat. 

There  is  one  important  fact  to  be  remembered :  plants 
have  the  ability  to  take  water,  mineral  matter  and  gases 
from  the  soil  and  air  and  combine  them  into  proteid, 
fat,  and  carbohydrates.  Animals  cannot  do  this  nor  can 
they  change  fat  and  carbohydrates  into  proteid,  but  must 
take  these  three  substances  from  the  vegetable  kingdom 
and  elaborate  them  for  their  own  particular  uses;  so  a 
perfect  food  must  contain  proteid,  fat,  and  carbohydrates  in 
proportions  suitable  to  the  needs  of  each  particular  animal. 

It  is  evident  that  a  cat  or  dog  would  starve  if  fed  hay 
and  grass,  and  that  a  horse  or  cow  would  not  as  a  rule 
thrive  on  raw  meat.  Human  beings  feed  on  meat  and 
vegetable  substances,  but  not  in  the  condition  in  which 
the  lower  animals  eat  them.  They  must  be  prepared  by 
a  cooking  process  before  the  human  digestive  apparatus 
can  act  to  advantage.  This  forces  the  conclusion  that  the 
digestive  system  of  each  kind  of  animal  must  be  particu- 
larly suited  to  its  natural  food.  As  young  animals  are 
miniatures  or  rudiments  of  their  parents,  their  digestive 
systems  must  be  in  a  general  way  like  those  of  their  pa- 
rents, so  it  would  be  natural  to  suppose  the  mother's  milk 
would  be  particularly  suited  to  the  young  animal's  diges- 
tion, and  that  the  milk  of  one  kind  of  animal  would  not 
suit  the  young  of  another  kind  any  more  than  the  food  of 
a  cat  would  suit  a  cow  or  a  horse.  It  is  the  substitution 
of  some  other  milk  that  causes  so  much  trouble  in  infant 
feeding.  Chemistry  has  never  been  able  to  show  why 
this  substitution  causes  trouble.  The  answer  has  been 
hinted  at, — different  digestive  systems.  In  the  following 
chapters  this  important  subject  will  be  treated. 


CHAPTER    IV. 

OBJECT  AND  PROCESSES  OF  DIGESTION- 
MECHANISM  AND  COMPARISONS  OF  DI- 
GESTIVE  TRACTS. 

5-  The  object  of  digestion  is  to  separate  from  the  food 
that  is  eaten  those  portions  that  will  serve  as  nutriment 
to  the  organism  from  those  that  are  useless,  and  to  put 
them  into  soluble,  absorbable  forms,  so  that  the  blood 
can  carry  them  to  every  part  of  the  body. 

The  process  of  digestion  consists  of  two  distinct  parts: 
(i)  a  mechanical  part,  and  (2)  a  chemical  part.  The  me- 
chanical part  consists  of  grasping,  tearing,  chewing,  or 
grinding  the  food ;  the  chemical  part  in  the  solvent  action 
of  the  various  digestive  juices. 

The  chemical  changes  that  take  place  in  a  particular 
kind  of  food  during  digestion  are  practically  the  same  in 
all  forms  of  animal  life,  but  the  mechanism  of  digestive 
tracts  varies  greatly,  and  the  kind  of  digestive  juices  that 
are  secreted  depends  largely  on  the  natural  food  of  the 
animal.  All  animals  must  have  protein  in  some  form  and 
all  have  digestive  juices  that  will  digest  it,  while  some 
animals  have  in  addition  digestive  juices  that  will  digest 
many  other  substances.  A  dog  whose  principal  food  is 
animal  protein  (meat)  does  not  need  a  digestive  juice  that 
will  soften  hay  or  grass,  and  does  not  have  it.  A  horse 
or  cow  needs  a  digestive  juice  that  will  soften  and  digest 


OBJECT   AND   PROCESSES   OF   DIGESTION.      17 

the  fibres  of  hay  or  grass  and  liberate  the  vegetable  protein 
they  contain,  when  the  same  chemical  change  in  the  pro- 
tein takes  place  as  in  the  dog's  digestion. 

The  discussion  of  what  are  the  chemical  changes  that 
take  place  during  digestion  will  be  deferred  until  the 
mechanism  of  digestion  has  been  briefly  considered. 

6.  To  furnish  a  dog  a  pound  of  protein,  about  four 
pounds  of  lean  meat  would  be  fed,  meat  being  about 
three-fourths  water;  to  supply  a  horse  a  pound  of  protein, 
about  thirty  pounds  of  grass  or  sixteen  pounds  of  dry  hay 
would  have  to  be  fed.  It  is  apparent  that  not  only  must 
the  digestive  system  of  a  horse  be  relatively  much  larger 
than  that  of  a  dog,  but  much  more  complicated. 

It  is  a  well-established  fact  that  the  more  complicated 
the  food  the  more  complicated  is  the  digestive  tract. 

When  a  jelly  fish  comes  in  contact  with  its  food  it 
folds  itself  around  it.  When  all  the  nutriment  has  been 
extracted  it  unfolds  again.  In  a  higher  form  of  life  the 
digestive  cavity  is  permanent  and  is  a  straight  tube.  As- 
cending in  the  animal  scale,  the  digestive  tract  becomes 
longer,  curved,  and  separated  into  distinct  parts  that  have 
special  functions.  Organs  for  grasping  the  food  are  pro- 
vided, and  the  character  of  the  food  and  the  digestive  sys- 
tem of  the  animal  can  often,  if  not  always,  be  known  by 
a  glance  at  these  structures.  - 

Animals  of  prey  have  teeth  adapted  for  tearing  flesh 
and  crushing  bones.  Their  gullets  are  distensible,  and 
they  can  swallow  great  pieces  of  meat  and  bones.  Their 
digestive  juices  are  particularly  adapted  for  dissolving 
meat  and  even  bone,  and  their  digestive  apparatus  is  short 
and  simple.     Their  stomachs  are  capacious,  being  sixty 


INFANT   FEEDING. 


to  eighty  per  cent  of  the  whole  digestive  tract,  and  the 

outlet  to  the  intestine  is  small  and  kept  closed  until  the 

food  is  liquefied,  thus  insuring  thorough  gastric  digestion. 

Herbivorous  animals,  like  the  cow,  goat,  sheep,  horse, 

and  ass,  have  teeth  for 
thoroughly  chewing  their 
food,  and  their  gullets  are 
small  and  non-distensible. 
With  the  cow,  goat, 
and  sheep,  the  food  is  first 
swallowed  without  chew- 
ing, and  goes  into  the 
paunch  or  rumen,  where  it 
is  softened  very  much  as 
is  the  food  in  a  bird's 
crop.  The  animal  lies 
down  and  at  its  leisure 
ruminates  or  rechews  the 
food,  which  then  goes  into 
the  fourth  stomach — these 
animals  have  four  stom- 
achs— where  it  is  princi- 
pally digested,  and  then 
passes  into  the  intestines 
through  a  small  outlet, 
which  allows  only  liquid  or 
semi-liquid  food  to  pass  out. 
The  stomach  of  the  cow,  goat,  and  sheep  comprises 
about  seventy  per  cent  of  the  digestive  tract. 

The  horse  and  ass,  which  eat  the  same  kind  of  food  as 
the  cow,  have  entirely  different  digestive  systems.     They 


Fig.  3. — Simple  Digestive  Tract  of  Carnivor- 
ous Animal  (Dog).  Stomach  sixty  to  eighty 
percent      (After  Bernard,  modified.) 


OBJECT  AND   PROCESSES   OF   DIGESTION.      19 

chew  their  food  once  for  all.     Their  stomachs  comprise 
only  eight  to  nine  per  cent  of  the  digestive  tract,  and  will 


Fig.  4.— Complicated  Digestive  Tract  of  Ox  or  Cow.    Stomach  seventy  per  cent.     (Chauveau.) 
(1)  Stomach.      (2)  Intestines. 

not  hold  more  than  one-third  to  one-half  of  a  meal.     The 
outlet  to  the  intestine  is  large  and  open,  and  while  the 


20 


INFANT   FEEDING. 


animal  eats  a  meal  the  food  passes  directly  into  the  intes- 
tine, which  at  the  farther  end  is  enormously  developed, 
forming  about  sixty  per  cent  of  the  entire  digestive  tract. 
Young  birds  of  prey  are  fed  flesh,  young  worm-eating 
birds  are  supplied  with  worms,  and  young  seed-eating 
birds  with  seeds.     Here  it  is  plain  that  the  digestive  sys- 


-Interior  of  Ox's  or  Cow's  Stomach.     (Chauveau.) 


terns  of  young  birds  are  very  much  the  same  as  those  of 
the  parents.  All  young  animals  that  are  suckled  are 
furnished  milk,  which  is  a  fluid,  while  the  parents'  food 
is  solid.  This  seems  to  be  different  than  in  the  case  of 
young  birds  which  receive  solid  food,  but  in  the  stomachs 
of  these  young  animals  is  found  rennet,  a  substance  that 
changes  milk  into  a  solid  or  semi-solid  condition.  Jun- 
ket is  a  familiar  example  of  cow's  milk  turned  into  a  solid. 


OBJECT   AND    PROCESSES  '  OF   DIGESTION.      21 

It  has  been  stated  that  rennet  seems  to  be  a  superfluous 
substance  in  the  stomach,  seeing  that  the  milk  is  again 


Fig.   6.— Complicated  Digestive  Tract  of  Horse.      (Y)  Stomach,  eight  to  nine  per  cent. 
(2)   Intestines,  ninety-one  to  ninety-two  per  cent.     (Chauveau) 

converted  into  a  fluid  by  the  digestive  process,  but  that 
this  is  not  so  will  be  seen  presently. 


22  INFANT   FEEDING. 

While  chemical  analyses  show  all  milks  to  be  alike  in 
containing  the  same  ingredients,  but  in  different  propor- 
tions, milks  differ  in  their  behavior  with  rennet,  and  as 
chemical  analyses  give  so  little  information  as  to  the  char- 
acter of  the  milk,  chemists  classify  milks  according  to  their 
behavior  with  rennet.  It  is  found  that  cow's,  goat's,  and 
sheep's  milk  form  solid  curds  when  acted  upon  by  rennet, 
which  even  when  broken  up  into  fine  particles  will  readily 
unite  again;  while  horse's  and  ass'  milk  form  a  fluid  jelly 
which  will  not  become  solid.  Human  milk  seems  to 
stand  between  these  two  types  of  milk. 

The  greater  part  of  the  digestion  of  cows,  goats,  and 
sheep  is  performed  in  their  stomachs,  which,  as  stated  be- 
fore, comprise  about  seventy  per  cent  of  their  whole  diges- 
tive system.  In  changing  the  milk  of  these  animals  into 
a  solid  that  cannot  easily  leave  the  stomach,  the  rennet 
causes  the  digestion  of  the  young  animal  to  take  place  in 
its  stomach,  the  same  as  in  the  case  of  the  parent. 

The  stomach  of  the  horse  or  ass,  being  only  eight  or 
nine  per  cent  of  the  digestive  tract,  will  not  hold  enough 
food  for  a  meal,  and  the  outlet  to  the  intestine  is  large,  so 
the  food  can  easily  leave  the  stomach,  which  it  does  con- 
tinuously during  a  meal.  The  milk  of  the  horse  or  ass 
does  not  form  a  solid  lump,  but  a  fluid  jelly  that  can  read- 
ily be  forced  into  the  intestine,  which  comprises  ninety 
per  cent  of  the  digestive  tract.  Here  again  it  is  plain 
that  the  mother's  milk  is  exactly  suited  physically  to  the 
digestive  tract  of  the  young  animal,  and  that  the  process 
of  digestion  of  the  young  animal  is  similar  to  that  of  the 
parent. 

In  human  beings,  which  eat  meat  and  vegetable  sub- 


OBJECT  AND   PROCESSES   OF   DIGESTION.     23 


stances,  the  digestive  system  is  adapted  for  either  class 
of  food,  but  the  food  must  be  prepared  for  digestion  by- 
thorough  chewing  of  meat  and  by  cooking  of  vegetable 
substances,  as  no  paunch  or  enlarged  intestine  is  fur- 
nished where  they  may  lie  and  soak  preparatory  to  diges- 
tion. 

The  human  stomach,  which  comprises  about  twenty 
per  cent  of  the  digestive  tract,  is  provided  with  a  small 
outlet  to  prevent  lumps  passing 
into  the  intestine.  This  small 
outlet,  teeth  for  dividing  every 
kind  of  food,  and  salivary 
glands  that  secrete  more  fluid 
than  the  kidneys,  show  that 
the  stomach  was  intended  to 
receive  soft,  finely  divided 
material  which  could  easily 
pass  into  the  intestine.  If  any 
proof  of  this  conclusion  was 
needed,  the  distress  that  is 
often  brought  on  by  hasty  eat- 
ing and  bolting  great  lumps  of 
food  would  furnish  it. 

Human  milk  does  not  form 
a  solid  lump  or  fluid  jelly  in 
the  stomach,  but  a  soft,  finely 
divided  mass. 

A  whole  book  could  be  written  showing  instances  of 
how  nature  adapts  an  animal  to  its  surroundings  and  food, 
but  from  the  few  instances  cited,  which  bear  particularly 
on  the  feeding  of  young  animals,  it  will  be  clear  that,  in 


Fig.    7.  —  Human     Digestive     Tract. 
Stomach,  twenty  per  cent.     (Leidy.) 


24  IXFAXT   FEEDING. 

physical  properties  at  least,  there  are  different  kinds  of 
milk  and  that  these  differences  are  not  freaks  of  nature 
or  inexplicable,  but  are  of  the  highest  importance  in  de- 
veloping the  young  animal's  digestive  system ;  also  that 
milks  are  not  interchangeable  from  a  digestive  standpoint. 
These  physiological  comparisons  throw  a  strong  side  light 
on  the  difficulties  necessarily  met  with  in  utilizing  the 
natural  food  of  one  species  for  the  nutriment  of  another. 

In  a  future  chapter  the  composition  of  milk  will  be  dis- 
cussed and  an  attempt  will  be  made  to  show  that  the  dif- 
ference in  composition  of  the  milk  of  various  animals 
is  closely  connected  with  the  natural  development  and 
growth  of  the  young  animals. 

Before  this  subject  is  taken  up,  a  little  space  will  be 
devoted  to  the  chemistry  of  food  and  digestion. 


CHAPTER  V. 

BROAD  CLASSIFICATION  OF  FOOD  INTO  PRO- 
TEIN, FAT,  CARBOHYDRATES,  MINERAL 
MATTER,  AND   WATER. 

7.  Food  is  generally  divided  into  four  great  classes: 

I.  Protein,  often  called  proteid  or  albuminoids. 

II.  Fat. 

III.  Carbohydrates. 

IV.  Mineral  matter  or  salts.  In  addition  to  these, 
water  is  a  very  important  ingredient  of  food,  as  it  enters 
into  the  composition  of  every  part  of  the  body,  the  bones 
even  being  over  ten  per  cent  water.  There  are  many 
other  important  ingredients  of  food,  but  they  are  not  gen- 
erally considered,  as  they  are  usually  found  with  one  of 
these  four  classes.  The  function  of  the  protein  of  food 
is  to  build  up  muscular  tissue;  fats  and  carbohydrates 
are  heat-producers,  and  mineral  matter  hardens  the  bones. 

I.  Protein.  The  exact  composition  of  protein  or  pro- 
teid has  never  been  discovered,  but  it  has  been  found  that 
the  different  forms  consist  of: 

Carbon 50. 6  -54.  5    per  cent. 

Hydrogen 6.  5  -  7-3 

Nitrogen (average  about  16  per  cent. )  15.0  -17.6 

Sulphur o.  3  -  2.2 

Phosphorus o.  42-  o. 85 

Oxygen 21.5  -23.  5 

Iron  is  also  found  in  some  forms  of  protein. 
These  figures  in  a  general  way  represent  the  composi- 
tion of  lean  beef,  pork,   mutton,  veal,  fowl,  fish,  and  of 


26  INFANT   FEEDING. 

the  total  proteid  of  milk  and  eggs.  Vegetable  proteids 
seem  to  have  about  the  same  composition  and  chemical 
properties  as  animal  proteids  (4). 

II.  Fatsaxe  entirely  different  from  proteids  in  compo- 
sition, being  composed  of  about: 

Carbon 76.  5  per  cent. 

Hydrogen 12.0        " 

Oxygen n.  5       " 

III.  Carbohydrates  form  the  chief  portion  of  the  dry 
substance  of  the  vegetable  kingdom. 

The  principal  carbohydrates  that  are  the  natural  food 
of  animals  are  starch,  found  in  potatoes  and  in  nearly  all 
the  grains,  and  cellulose  or  the  framework  of  plants. 

For  human  food,  starch,  in  the  form  of  cereals  and 
bread ;  glucose,  found  in  grapes,  raisins,  molasses,  and  syr- 
up ;  cane  siigar,  or  the  familiar  granulated  sugar,  which  is 
found  in  sugar  cane,  beets,  carrots,  and  the  maple  tree ; 
and  milk  sugar,  found  in  milk,  are  the  principal  carbohy- 
drates used.  All  these  are  composed  of  carbon,  hydro- 
gen, and  oxygen,  there  being  two  parts  of  hydrogen  for 
each  part  of  oxygen,  which  is  the  proportion  in  which 
these  elements  combine  to  form  water,  FLO.  Hence  the 
carbon  is  hydrated,  and  the  name  carbohydrates. 

Cellulose      consists  of CeHioOo  or  C6(H20)5 

Starch  "  "    C6Hio05 

Glucose  "         "   CeHjoOs 

Cane  sugar      "         "      C12H22O11 

Milk  sugar      "         "    C12H22O11 

Chemically  the  only  difference  between  all  these  car- 
bohydrates is  the  quantity  of  water  (H20)  combined  with 
the  carbon.  Physically  there  are  great  differences.  Milk 
sugar  and  cane  sugar,  which  have  the  same  composition, 


BROAD    CLASSIFICATION  OF   FOOD.  27 

are  different  from  each  other,  as  also  are  cellulose  and 
starch. 

IV.  Mineral  matter  is  found  in  all  forms  of  food,  but 
it  is  hard  to  tell  much  about  the  state  or  combination  in 
which  it  exists. 

8.  In  comparing  the  composition  of  proteids,  fats,  and 
carbohydrates,  it  will  be  noticed  that  the  proteids  are  very 
complex  and  contain  a  fairly  constant  percentage  of  nitro- 
gen, which  is  not  found  at  all  in  the  fats  and  carbohy- 
drates. As  proteid  takes  such  a  variety  of  forms,  the 
only  practical  method  of  determining  it  quantitatively  is 
to  determine  the  quantity  of  nitrogen  in  the  food  and 
consider  it  sixteen  per  cent  of  the  total  proteid,  as  all  pro- 
teid contains  about  sixteen  per  cent  of  nitrogen.  The 
weight  of  proteid  is  found  by  multiplying  the  weight  of 
the  nitrogen  by  6.25  (16  per  cent  X  6.25  =  100). 

It  is  not  pretended  that  this  method  is  exact,  but  it  is 
the  best  that  can  be  devised  and  answers  all  practical  pur- 
poses. The  lecithin,  which  is  a  kind  of  fat,  is  included 
with  the  proteid,  as  it  contains  nitrogen. 

Fats  are  determined  by  extracting  the  food  with  ether 
or  other  fat  solvents. 

Carbohydrates  cannot  be  determined  directly.  It  is 
customary  in  most  food  analyses  to  determine  proteid, 
fat,  water,  and  mineral  matter,  add  their  weights  together, 
and  call  the  remainder  carbohydrates. 

Mineral  matter  is  determined  by  burning  some  of  the 
food  and  weighing  the  ash. 

9-  It  is  easy  to  see  that  a  mere  chemical  analysis  is  not 
a  safe  guide  in  selecting  a  food  for  an  animal,  for  a  dog 
could  not,  on  account  of  its  simple  digestive  system,  get 


28 


INFANT   FEEDING. 


at  the  protein  or  fat  of  whole  corn,  for  instance.  It  would 
starve  with  a  stomach  full  of  food  that  would  nourish 
if  it  could  only  digest  it ;  after  the  corn  was  ground  and 
cooked,  the  dog  could  digest  it.  This  has  led  to  a  physi- 
ological test  to  see  how  much  of  a  certain  kind  of  food 
each  species  of  animal  can  digest  and  assimilate.  A  meal 
is  weighed,  and  the  fat,  proteid,  carbohydrates,  and  mine- 
ral matter  are  determined.  The  animal  is  then  given  a 
capsule  of  lampblack  and  a  little  later  is  fed  the  meal ;  be- 
fore the  next  meal  another  capsule  of  lampblack  is  given. 
The  discharges  from  the  bowels  are  collected,  and  what 
is  between  the  two  lampblack  marks  contains  what  was 
left  undigested  from  the  meal.  This  excrement  is  ana- 
lyzed and  the  digestibility  of  the  meal  determined. 

By  this  method  some  old  theories  of  feeding  have 
been  completely  upset,  for  it  had  been  assumed  that  many 
foods  were  just  what  was  needed  because  chemical  analy- 
ses showed  them  to  contain  large  quantities  of  nutri- 
tious substances.  Digestion  tests,  however,  showed  that 
they  were  not  digested,  and  so  of  course  there  was  no  ad- 
vantage in  using  the  foods.  A  great  many  of  these  tests 
have  been  made  on  farm  animals,  and  the  following  analy- 
sis will  give  an  idea  of  the  results : 


Water. 

Ash. 

Protein. 

hydrates. 
Per  cent. 

Per  cent. 

Per  cent 

Per  cent. 

61.6 

2.1 

3-1 

32.OO 

6l.6 

? 

2.28 

23.71 

13.2 

4-4 

5-9 

74.OO 

13.2 

? 

2.89 

43-72 

II. O 

3-0 

11. 8 

69.2 

II. O 

? 

9-25 

48-34 

87.2 

0.7 

3-6 

4-9 

87.2 

3.4S 

4-7 

Fat. 
Per  cent. 


Timothy  grass  contained 

"         digestible 

' '         hay  "  

"         digestible 

Oats  contained 

"         digestible 

Cow's  milk  contained 

"         digestible  .  . 


1.20 

•  77 
2-5 
1-43 
5-0 
4.18 
3-7 
3-7 


CHAPTER    VI. 

THE  CHEMICAL  PROCESSES  OF  DIGESTION- 
COMPARATIVE  DIGESTION  AND  ABSORP- 
TION  IN   DIFFERENT   ANIMALS. 

io.  Before  any  food  that  is  eaten  can  be  of  use  to  the 
organism  it  must  be  chemically  changed  so  that  it  can  pass 
into  the  blood  in  suitable  form.  Each  animal  is  fur- 
nished with  digestive  juices  that  produce  the  requisite 
changes  in  its  natural  food,  but  just  what  these  changes 
are  or  how  they  take  place  is  not  thoroughly  understood. 
The  kind  of  digestive  juice  that  is  secreted  depends 
largely  on  the  food  that  is  eaten.  In  the  lower  forms  of 
animal  life,  as  the  jelly  fish,  which  folds  itself  around  its 
food,  it  is  found  that  if  animal  food  is  taken,  a  digestive 
juice  that  will  digest  meat  is  secreted ;  if  vegetable  food 
is  taken,  a  digestive  juice  that  will  digest  vegetable  sub- 
stances is  secreted.  As  it  was  shown  (6)  that  the  more 
complex  the  food  of  an  animal  is,  the  more  complex  is  its  di- 
gestive system,  so  it  will  be  found  that  the  more  complex 
the  digestive  system,  the  greater  number  of  digestive 
juices  there  are  secreted,  each  distinct  portion  of  the  di- 
gestive tract  having  a  peculiar  digestive  juice  particularly 
adapted  to  the  condition  of  the  food  when  it  reaches  it. 

In  animals  that  live  on  flesh,  a  strong  juice  that  dis- 
solves meat  and  even  bone  is  found  in  the  stomach.  The 
food  does  not  need  to  be  chewed  or  moistened  before 


30  INFANT   FEEDING. 

swallowing,  and  consequently  little  saliva  is  secreted. 
Here  digestion  is  simple  and  the  digestive  tract  is  corre- 
spondingly simple  (see  Fig.  3). 

When  it  comes  to  herbivorous  animals,  like  the  cow, 
goat,  and  sheep,  the  digestive  system  becomes  exceed- 
ingly complex  (see  Fig.  4).  When  hay  is  eaten  it  must 
be  softened,  and  the  ox  secretes  ten  to  twelve  gallons  of 
saliva  a  day;  when  grass  is  eaten,  only  one-third  as  much 
saliva  is  secreted.  The  food  of  these  three  animals  goes 
to  the  paunch  or  rumen  and  soaks  until  the  cellulose 
(crude  paper)  that  envelops  the  nutritious  portions  of  the 
food  is  softened  and  partly  digested  when  the  food  is  re- 
gurgitated and  rechewed,  and  then  passes  into  the  true 
stomach  where  digestion  principally  takes  place.  In  birds 
with  crops  and  gizzards  practically  the  same  process  is  ob- 
served. The  goat's  fondness  for  bill  posters  and  labels  is 
not  altogether  the  result  of  degeneration.  It  can  digest 
part  of  the  paper  and  all  the  flour  paste  on  it. 

With  the  horse,  mule,  and  ass,  which  eat  the  same 
kind  of  food  as  the  cow,  goat,  and  sheep,  the  order  in 
which  the  digestive  juices  act  is  different.  Their  food  is 
chewed  with  the  saliva  before  it  is  swallowed,  and  the  ex- 
posed portions  that  are  easily  digested  are  dissolved  and 
the  remainder  of  the  food  is  passed  into  the  caecum  at  the 
far  end  of  the  intestine  (see  Fig.  6),  which  holds  as  much 
as  a  cow's  paunch,  where  the  cellulose  is  partly  dissolved, 
allowing  the  enclosed  nutriment  to  be  then  digested. 
With  cows,  etc.,  digestion  takes  place  principally  at  the 
beginning  of  the  digestive  tract ;  with  the  horse  and  ass, 
at  the  end  of  it. 

It  might  be  truthfully  said  that  the  great  difference  in 


CHEMICAL   PROCESSES   OF  DIGESTION.         31 

the  food  of  animals  (for  all  must  have  protein,  fat,  carbo- 
hydrates, and  mineral  matter)  lies  in  the  fact  that  the  food 
of  herbivorous  animals  is  wrapped  up  in  cellulose  (paper), 
while  the  food  of  carnivorous  animals  and  human  beings 
is  not  enclosed  in  cellulose.  After  this  wrapping  is  re- 
moved from  the  food  there  is  very  little  difference  in  the 
ability  of  different  species  of  animals  to  produce  the  nec- 
essary chemical  changes  in  the  same  food.  Nature  is 
very  elastic  on  the  food  question,  and  in  selecting  a  diet 
it  is  not  so  necessary  to  pay  attention  to  fine  points  as  to 
whether  the  food  contains  all  the  necessary  elements  and 
to  their  physical  condition.  Human  beings  cannot  take 
their  animal  food  in  huge  pieces  as  do  carnivorous  ani- 
mals, nor  their  vegetable  food  in  the  form  herbivorous 
animals  find  convenient.  Meat  must  be  chewed  and  veg- 
etable substances  cooked  to  break  open  the  envelopes  of 
cellulose.  Each  little  starch  grain  has  a  coat  of  cellulose 
on  it,  upon  which  the  human  digestive  juices  have  little 
action.  Cooking  starch  by  boiling  or  baking,  as  in  bread, 
breaks  these  coats  open  and  then  the  starch  is  readily 
digested  (103,  105). 

11.  The  chemical  changes  in  the  food  are  brought 
about  by  enzymes  found  in  the  digestive  juices.  These  en- 
zymes have  never  been  isolated  in  a  pure  state,  and  what 
they  are  is  not  known.  Their  presence  can  be  detected 
only  by  their  action  on  food.  There  seems  to  be  a  par- 
ticular kind  of  enzyme  for  each  kind  of  food. 

In  human  saliva  is  found  ptyalin  (diastase),  which  con- 
verts cooked  starch  into  dextrin  and  maltose.  In  the  gas- 
tric juice  is  found  pepsin,  which  is  secreted  along  with 
hydrochloric  acid,  which  converts  proteid  into  albumoses 


32  INFANT   FEEDING. 

and  peptones.  Gastric  juice  has  a  strong  solvent  action 
on  the  connective  materials  that  bind  the  muscular  fibres 
together  and  causes  meat  to  swell  up  and  disintegrate  into 
fine  particles. 

The  greater  part  of  human  digestion  is  performed  in 
the  intestine,  so  the  action  of  the  saliva  in  digesting  the 
exposed  starch  and  the  action  of  the  gastric  juice  in  disin- 
tegrating the  connective  material  of  meat  and  vegetable 
proteids  are  preparatory  to  intestinal  digestion  and  must 
be  important. 

Fat,  sugar,  and  starch  are  not  acted  upon  by  the  gas- 
tric juice,  and  when  present  in  excessive  quantities  in- 
terfere with  its  secretion.  Fat  and  starch,  by  coating 
proteids,  prevent  the  action  of  the  gastric  juice  and  throw 
the  work  of  the  stomach  on  to  the  intestines.  Soaking 
bread  in  tea  or  coffee  or  washing  down  food  with  water 
does  away  with  the  action  of  the  saliva  on  the  starches, 
and  filing  food  coats  it  with  fat  so  that  neither  the  saliva 
nor  gastric  juice  can  well  act  on  it.  Pork,  on  account  of 
its  containing  so  much  fat,  is  particularly  indigestible. 

In  the  intestine  are  found  enzymes  that  will  convert 
proteids  into  albumoses  and  peptones,  but  intestinal  di- 
gestive juice  does  not  cause  proteid  to  swell  up  and  disin- 
tegrate first,  as  does  the  gastric  juice ;  starch  that  escaped 
the  action  of  the  saliva  is  converted  into  dextrin,  maltose, 
and  dextrose ;  cane  sugar  into  dextrose  and  levulose ;  and 
milk  sugar  into  dextrose  and  galactose.  As  far  as  chem- 
istry shows,  all  these  changes  consist  of  the  chemical  ad- 
dition of  water  to  the  original  proteid  or  carbohydrate. 
The  actual  changes  have  never  been  discovered.  There 
are  also  found  in   the  intestine  enzymes  that  split  and 


CHEMICAL   PROCESSES    OF   DIGESTION.         33 

emulsify  fats.     Some  of  these  enzymes  are  secreted  by 
the  pancreas,  and  others  by  glands  of  the  intestines. 

These  enzymes  seem  to  act  by  contact,  and  to  act  best, 
the  food  must  be  finely  divided  and  pulpy.  Their  diges- 
tive power  is  enormous.  One  part  of  crude  invertase 
digested  one  hundred  thousand  times  its  weight  of  cane 
sugar,  and  was  still  active. 

12.  The  process  of  human  digestion  differs  from  that  of 
the  lower  animals,  in  that  the  vegetable  food  must  be  pre- 
pared outside  of  the  body  to  rupture  the  cellulose  envel- 
opes, and  the  animal  food  chewed.  The  food  then  is  to 
be  first  treated  with  a  starch-digesting  fluid,  the  saliva,  to 
expose  the  proteid ;  next  with  the  gastric  juice  which  dis- 
integrates proteid  and  reduces  it  to  a  pulpy  jelly,  and 
then  only  will  the  pylorus  naturally  open  to  allow  food  to 
pass  into  the  intestine,  where  the  greater  part  of  the 
chemical  changes  in  the  food  take  place  previous  to  ab- 
sorption. 

13.  The  secretion  of  the  digestive  juices  is  under  the 
control  of  the  nervous  system.  The  thought  of  an  appetiz- 
ing meal  makes  the  mouth  water,  and  the  food  is  then 
pretty  apt  to  be  digested.  Pleasant-tasting  food  taken 
into  the  mouth  also  excites  the  secretion  of  the  digestive 
juices. 

The  absorption  of  certain  substances  from  the  diges- 
tive tract  strongly  excites  the  secretion  of  all  the  digestive 
juices.  Among  the  substances  that  act  as  promoters  of 
digestive  secretion  are  the  products  of  salivary  digestion 
of  starch  (dextrin  and  maltose),  and  the  extractives  of 
meat  (2).  Substances  which  have  the  power  of  stimulating 
digestive  secretion  are  also  found  in  milk. 


34  INFANT   FEEDING. 

14.  The  process  of  digestion  is  laborious  at  the  best, 
one-sixth  of  the  entire  force  of  the  organism  being  required 
to  digest  an  average  meal ;  so  an  indigestible  meal  that  re- 
quires prolonged  digestive  secretion,  or  has  to  be  digested 
in  the  intestine  without  preparation  in  the  mouth  and 
stomach,  causes  great  weariness. 

Excessive  quantities  of  fat  in  the  stomach  retard  not 
only  the  digestion  of  proteid  by  coating  it,  but  also  retard 
the  secretion  of  the  gastric  juice  and  cause  loss  of  appe- 
tite. Excessive  quantities  of  sugar  cause  the  stomach  to 
secrete  an  unusually  acid  gastric  juice,  which  interferes 
with  digestion.  These  two  facts  should  be  remembered, 
as  they  have  great  practical  value  in  infant  feeding. 

Nervous  shock  or  excitement  interferes  with  normal 
digestive  secretion. 

15.  Just  how  much  of  each  of  the  digestive  juices  is 
secreted  is  not  known,  but  an  adult  secretes  more  saliva 
than  urine.  There  seems  to  be  a  continuous  flow  of  di- 
gestive juice  and  absorption  of  digested  food  during  the 
process  of  digestion.  The  process  of  absorption  of  pro- 
teid is  not  known.  Some  change  takes  place  in  the  di- 
gested proteids  during  their  passage  through  the  walls  of 
the  digestive  tract  into  the  blood,  for  the  products  of  pro- 
teid digestion  are  not  found  in  the  blood,  and  if  injected 
into  the  blood  are  eliminated  unchanged  by  the  kidneys. 
Fats  are  emulsified  and  absorbed  with  little  change. 

16.  After  the  digested  food  has  passed  from  the  diges- 
tive tract  into  the  blood,  it  must  be  carried  to  the  cells  in 
every  part  of  the  body.  This  does  not  take  place  sud- 
denly but  gradually.  Those  portions  of  the  digested  food 
that  are  not  immediately  required  are  stored  up  for  future 


CHEMICAL   PROCESSES   OF   DIGESTION.         35 

use.  The  excess  of  carbohydrates  is  stored  away  in  the 
muscles  and  liver  in  the  form  of  glycogen,  which  is  simi- 
lar in  composition  to  starch ;  a  great  excess  of  carbohy- 
drates is  eliminated  by  the  kidneys  or  converted  into  fat. 
Excess  of  fat  is  stored  away  as  fat.  Proteids  are  not 
stored  up  in  the  adult,  any  excess  being  excreted,  as  will 
be  explained  in  the  next  chapter. 

i7-  When  an  animal  is  not  fed  at  all,  the  processes  of 
life  continue  for  a  certain  time,  but  there  is  a  steady  loss  of 
weight.  The  glycogen  stored  in  the  liver  disappears 
almost  completely ;  the  stored-up  fat  also  disappears,  and 
all  the  muscles  shrink  away,  and  at  last  the  animal  dies. 

For  a  long  time  it  was  not  known  how  the  tissues  fed 
upon  themselves,  but  it  has  been  recently  discovered  that 
in  the  blood  there  are  enzymes  that  will  digest  glycogen 
or  animal  starch,  converting  it  into  dextrin,  maltose,  and 
dextrose,  which  is  then  carried  to  the  portions  of  the 
body  where  it  is  most  needed  and  again  converted  into 
glycogen.  This  is  found  to  be  the  case  even  in  the  foe- 
tus. This  same  process  must  take  place  with  fats  and 
proteids,  but  the  enzymes  that  produce  the  changes  or 
what  is  the  nature  of  the  changes  in  the  proteids  have  not 
been  discovered. 

These  enzymes  that  act  in  the  system  are  called  en- 
zymes of  translocation,  and  have  somewhat  different 
modes  of  action  from  those  of  the  digestive  enzymes. 
They  have  been  better  studied  in  the  vegetable  kingdom, 
and  their  action  can  readily  be  appreciated  by  watching 
a  potato  sprout  in  a  dark  cellar  or  in  the  changing  of  a 
sprouting  pea  or  a  bean  into  root,  stem,  and  a  pair  of 
leaves. 


CHAPTER    VII. 
METABOLISM   AND    EXCRETION. 

18.  The  process  by  which  the  digested  food  is  built  up 
into  living  tissue,  and  the  living  tissue  and  food  are  re- 
duced to  other  and  simpler  dead  forms,  is  called  metabolism. 
This  process  is  going  on  continually  in  the  organism ;  the 
object  of  food  is  to  replace  the  loss  caused  by  destructive 
metabolism  and  to  build  up  new  tissue.  There  can  be  no 
scientific  feeding  without  a  knowledge  of  the  functions 
of  each  kind  of  food,  how  it  is  changed  in  the  organism, 
what  are  its  by-products,  and  how  they  are  excreted. 

19.  Fats  and  carbohydrates  composed  of  carbon,  hy- 
drogen, and  oxygen  are  completely  burned  in  the  body  by 
the  inhaled  oxygen  of  the  air,  into  carbon  dioxide  and 
water,  which  are  excreted  principally  through  the  lungs. 
These  two  food  principles  are  mostly  used  2&fuel\.o  sup- 
ply the  necessary  heat  to  keep  the  body  warm  and  fur- 
nish living  force. 

Proteids  can  also  act  as  fuel,  but  are  incompletely 
burned  in  the  body.  The  carbon  dioxide  produced  in  the 
metabolism  of  proteid  is  thrown  off  by  the  lungs,  but  the 
distinctive  by-products  of  proteid  metabolism  are  carried 
off  by  the  urine  in  the  form  of  urea,  uric  acid,  phosphates, 
sulphates,  and  other  salts;  so  a  study  of  the  urine  is  very 
important. 

20.  In  practice,  to  determine  the  quantity  of  proteid 


METABOLISM   AND    EXCRETION.  37 

that  is  being  actually  consumed  in  the  body,  it  is  only  nec- 
essary to  determine  the  quantity  of  nitrogen  in  the  urine 
and  multiply  by  6.25  (8),  which  gives  the  weight  of  the  pro- 
teid.  It  is  a  singular  fact  that  in  an  adult  animal  there 
is  what  is  called  a  nitrogenous  equilibrium — that  is,  the 
amount  of  nitrogen  eliminated  equals  the  amount  taken 
in  as  food.  If  the  fats  and  carbohydrates  are  fed  in  ex- 
cess of  the  requirements  of  the  body,  they  are  generally 
stored  up  as  fats,  but  with  proteids  it  is  different;  an 
increase  of  proteid  in  the  food  produces  an  increase  in 
the  quantity  of  nitrogen  in  the  urine,  and  in  a  few  days 
the  quantity  of  nitrogen  excreted  equals  the  quantity 
taken  in  as  food.  Possibly  the  excess  of  proteid  is  not  all 
wasted,  it  may  be  partly  changed  into  fat,  but  the  only  way 
an  increase  of  proteid  in  the  body  can  be  brought  about 
in  an  adult  is  by  muscular  activity,  which  increases  the 
size  of  the  muscles.  Inactivity  increases  fat.  Activity 
decreases  fat  and  increases  proteid  up  to  a  certain  point. 
Growing  animals  that  are  laying  on  proteid  are  full  of 
activity  and  playful,  which  they  cease  to  be,  as  a  rule, 
when  fully  grown. 

21.  The  amount  of  nitrogen  that  is  eliminated  in  the 
urine  depends  on  the  animal's  food ;  the  urine  of  carnivor- 
ous animals  is  rich  in  nitrogen,  while  the  urine  of  herbivor- 
ous animals  is  poor  in  nitrogen,  which  shows  that  in  the 
flesh-eating  animals  large  quantities  of  proteid  are  being 
consumed  as  fuel,  while  in  the  vegetable-eating  animals, 
whose  food  is  principally  carbohydrates,  small  quantities 
of  proteid  are  thus  consumed. 

22.  When  animals  are  starved  they  immediately  com- 
mence to  live  on  their  own  flesh  and  become  carnivorous. 


38  INFANT    FEEDING. 

Experiments  made  with  metabolism  during  starvation 
show  that  the  urine  of  the  herbivorous  animals  becomes 
the  same  as  that  of  the  carnivorous  animals  in  every  way. 
The  stock  of  carbohydrates  (glycogen)  that  is  stored  up 
in  the  liver  of  all  animals  disappears  after  a  few  hours  of 
starvation,  and  then  the  fat  and  proteids  begin  to  disap- 
pear. 

During  starvation  the  temperature  of  the  animal  re- 
mains about  the  same  as  in  health,  and  the  amount  of  ni- 
trogen in  the  urine,  while  less  in  quantity,  is  the  same  in 
proportion  to  the  weight  of  the  animal  as  it  was  in  health 
in  the  case  of  carnivorous  animals,  and  greatly  in  excess 
of  the  quantity  in  health  in  the  case  of  herbivorous  ani- 
mals whose  diet  is  principally  carbohydrates.  Hence 
herbivorous  animals  do  not  stand  starvation  so  well  as  the 
carnivorae.  Metabolism  is  very  active  in  young  animals. 
Children  die  of  starvation  after  about  four  or  five  days, 
while  adults  can  often  starve  twenty  days  without  lasting 
injury. 

Just  before  death  from  starvation  the  quantity  of  ni- 
trogen in  the  urine  increases  greatly;  then  the  tempera- 
ture drops  below  normal,  and  the  animal  dies — the  fire  has 
gone  out.  Upon  examination  of  the  animal  it  is  found 
that  all  the  fat  of  the  body  has  disappeared,  even  the  bones 
having  lost,  and  the  proteid  has  been  drawn  on  until  the 
muscles  of  the  heart  are  too  weak  to  act.  The  increase 
of  nitrogen  in  the  urine  just  before  death  marked  the  time 
when  all  the  fat  had  been  used  up  and  the  proteid  had  to 
be  drawn  on  exclusively  for  fuel. 

23.  If  a  starving  animal  is  fed  carbohydrates  or  fats  the 
quantity  of  nitrogen  eliminated  in  the  urine  is  greatly  re- 


METABOLISM  AND   EXCRETION.  39 

duced  and  the  animal  loses  weight  less  rapidly,  but  event- 
ually dies,  as  these  food  elements  cannot  be  converted 
into  proteid  and  there  is  always  a  certain  consumption  of 
proteid.  Fats  and  carbohydrates  are  proteid  sparers,  car- 
bohydrates being  more  effective  than  fats.  The  knowl- 
edge of  how  to  take  advantage  of  this  fact  is  of  great 
value  in  the  treatment  of  diarrhoea  and  fevers  in  which 
there  is  increased  destruction  of  proteid  with  decreased 
elimination  of  urine,  and  in  kidney  affections  in  which 
the  urea  cannot  be  eliminated  normally. 

24.  If  a  healthy  carnivorous  animal  is  fed  albumin 
(white  of  egg),  which  is  a  form  of  protein,  it  will  die  from 
starvation  in  about  two  months.  Death  from  starvation 
will  also  follow  if  fats  and  carbohydrates  are  fed  along  with 
albumin,  fibrin,  or  gelatin,  which  are  all  forms  of  protein. 
Attempts  at  separating  different  forms  of  protein  for  food 
purposes  are  not  to  be  recommended,  as  grave  errors  in 
nutrition  are  likely  to  be  the  result.  This  much  is 
known:  the  protein  found  in  meat,  whole  milk,  grass, 
and  cereals,  when  given  in  the  original  state  without 
attempts  at  separation  into  distinct  classes  or  forms,  will 
support  life  and  produce  good  healthy  tissue ;  but  just 
what  part  each  form  of  protein  plays  in  nutrition  is  not 
known.  The  form  of  fat  and  carbohydrate  can  be 
changed  with  little  or  no  ill  effect,  but  to  assume  if  a 
form  of  food  which  contains  sixteen  per  cent  nitrogen 
and  is  digestible  is  given  for  protein  that  perfect  nutrition 
will  follow,  is  a  policy  that  may  lead  to  anaemia,  rickets, 
or  other  forms  of  malnutrition. 

25.  It  will  be  seen  from  the  foregoing  that  the  functions 
of  the  fat  and  carbohydrates  of  the  food  are  principally  to 


4o  INFANT   FEEDING. 

supply  heat  and  living  force,  and  those  of  the  proteid  to 
build  the  growing-  tissue  and  to  repair  waste ;  also  that 
when  the  waste  in  the  tissue  has  been  made  good  from 
the  food,  the  excess  of  proteid  in  the  food  is  burned  and 
eliminated  and  not  stored  up  as  proteid  in  the  adult. 
From  a  fuel  standpoint,  fat,  carbohydrate,  and  proteids 
are  interchangeable  in  about  these  proportions:  fat,  2}{  ; 
proteid,  i ;  carbohydrate,  i  ;  but  from  a  tissue-building 
standpoint  they  are  not.  This  knowledge  has  led  to  the 
use  in  animal  feeding  of  what  is  called  a  balanced  diet ;  that 
is,  a  diet  which  contains  enough  digestible  fat  and  carbo- 
hydrates to  furnish  heat,  and  enough  proteid  to  prevent  a 
loss  of  proteid  tissue.  This  point  is  determined  by  find- 
ing whether  the  nitrogen  in  the  proteid  of  the  food  equals 
the  nitrogen  in  the  urine.  The  amount  of  proteid  re- 
quired in  the  food  depends  largely  on  the  animal.  Wool- 
producing  animals,  as  the  sheep  and  goat,  need  more  pro- 
teid than  is  actually  used  in  the  vital  process  in  order  to 
form  the  wool  and  hair;  and  milk-producing  animals 
need  more  proteid  in  the  food  than  those  of  the  same 
species  that  are  not  secreting  milk,  as  from  three  to  four 
per  cent  of  the  milk  is  proteid.  In  an  adult  animal  it  is  a 
waste  to  give  much  more  nitrogen  (proteid)  in  the  food 
than  is  found  in  the  urine  during  a  period  of  fasting  under 
the  same  conditions  of  living,  as  the  only  result  is  to 
throw  extra  work  on  the  digestive  and  excretory  systems 
with  no  gain  to  the  organism.  With  children  and  young 
animals  there  should  be  more  nitrogen  (proteid)  in  the 
food  than  is  found  in  the  urine,  as  they  need  it  to  pro- 
duce new  growth  of  tissue,  and  true  growth  consists  of 
increasing  the  quantity  of  proteid  in  the  body. 


METABOLISM   AND    EXCRETION.  41 

26.  In  artificial  infant  feeding  the  great  difficulty  lies  in 
supplying  proteid  suitable  to  the  infant's  needs  and  diges- 
tion, and  the  great  temptation  is  to  cut  it  down  in  quantity 
or  supply  it  in  forms  that  are  very  easily  digested.  The 
result  is  that  either  not  enough  proteid  to  produce  much 
healthy  growth  is  furnished,  or  a  large  quantity  of  a  form 
of  proteid  that  cannot  do  more  than  retard  the  infant's 
consumption  of  its  own  tissue  is  given,  and  a  poorly  devel- 
oped child  is  often  the  result.  This  is  an  error  that  is 
almost  sure  to  result  from  a  diet  based  simply  on  a  chem- 
ical analysis. 

27.  During  the  process  of  digestion  there  is  a  greatly 
increased  destructive  metabolism  of  carbohydrates,  fully 
fifteen  per  cent  greater  than  in  fasting  under  the  same 
conditions,  and  also  a  slight  increase  in  the  destructive 
metabolism  of  proteid.  Examination  of  the  glands  secret- 
ing the  digestive  juices  shows  that  they  absorb  lymph, 
which  is  in  some  way  changed  into  digestive  juice  and 
then  secreted.  Here  is  a  source  of  slight  loss  of  proteid 
during  digestion,  for  this  proteid  matter  is  not  all  ab- 
sorbed, but  goes  in  part  to  make  up  fecal  matter.  It  is 
supposed  by  many  that  the  faeces  consist  of  undigested 
food.  This  is  true  to  but  a  slight  extent.  Fecal  matter 
consists  almost  wholly  of  secretions  from  the  digestive 
tract.  The  intestines  of  a  new-born  infant  contain  fecal 
matter — meconium.  A  starving  animal  produces  fecal 
matter  similar  to  meconium,  and  a  perfectly  clean  loop 
of  the  intestine  will  secrete  feces. 

The  character  and  quantity  of  the  fecal  matter  de- 
pend largely  on  the  food  that  is  eaten.  On  an  exclusive 
meat  diet  it  is  scanty,  black,  and  pitch-like,  and  quite  sim- 


42  INFANT   FEEDING 

ilar  to  that  from  a  starving  animal,  which  is  living  on  its 
own  tissues.  When  fat  is  added  to  the  food  the  fecal 
matter  contains  fat  and  is  lighter  in  color,  When  vege- 
table substances  are  added  to  the  diet  the  quantity  of  fae- 
ces increases  and  the  color  changes  with  the  character  of 
the  food.  The  increased  quantity  consists  in  part  of  un- 
digested food,  but  principally  of  the  increased  secretions 
of  the  mucous  membrane  of  the  intestine,  caused  by  the 
coarseness  of  the  food  and  the  mechanical  action  of  the 
undigested  portions. 

In  health  the  color  of  the  fecal  matter  depends  on  the 
kind  of  food.  Bile  pigments,  calomel,  and  senna  produce 
a  green  color,  iron  and  bismuth  a  black,  and  rhubarb  a 
yellow  color. 

In  normal  digestion  of  human  beings  there  should  be 
little  undigested  food  in  the  fecal  matter,  so  an  examina- 
tion of  the  stools  is  of  the  greatest  importance  in  feeding 
infants — in  fact,  is  absolutely  essential  to  success  (156). 


CHAPTER    VIII. 

COMPARISON  OF  THE  MILK  OF  DIFFERENT 
ANIMALS.  CHEMICAL  AND  PHYSIOLOGI- 
CAL  DIFFERENCES. 

28.  The  milk  of  all  animals  must  contain  the  materials 
necessary  for  the  nourishment  of  their  young.  Chemical 
examination  of  milks  shows  them  all  to  agree  in  contain- 
ing water,  fat,  proteids  or  albuminoids,  carbohydrates,  and 
mineral  matter.  In  addition  to  these  ingredients,  lecithin, 
cholesterin,  citric  acid,  and  other  substances  are  found  in 
varying  proportions. 

The  present  knowledge  of  the  chemical  composition 
of  milk  can  be  best  appreciated  by  the  following  quota- 
tions from  recent  high  authorities  upon  the  chemistry  of 
milk: 

"  Our  present  knowledge  of  the  albuminoids  of  milk  is 
far  from  complete,  though  much  work  has  been  done  on 
the  subject.  This  is  due  to  the  fact  that  it  is  extremely 
difficult  to  obtain  these  compounds  in  anything  like  a 
state  of  purity.  .  .  .  As  there  is  no  means  of  knowing  when 
all  the  impurities  have  been  eliminated,  it  is  possible  that 
we  are  yet  unacquainted  with  the  albuminoids  of  milk  in 
a  state  of  purity.  This  should  not  be  forgotten  during 
the  study  of  the  milk  albuminoids. 

"  In  the  albuminoids,  the  milks  of  different  animals 
differ  greatly.     They  may  be  divided  broadly  into  two 


44  INFANT   FEEDING. 

classes — those  which  give  a  curd  on  the  addition  of  an 
acid,  and  those  which  do  not.  In  the  first  class  are  in- 
cluded the  milk  yielded  by  the  cow,  the  goat,  the  gamoose, 
etc.;  and  in  the  second,  human  milk,  that  of  the  mare 
and  the  ass  may  be  cited  as  examples.  In  the  first 
class  the  curd  is  composed  of  casein,  which  is  combined 
with  phosphates  of  the  alkaline  earths;  while  in  the 
second  this  is  replaced  by  a  similar  albuminoid,  which  is 
not,  however,  combined  with  phosphates.  It  is  possible 
that  the  difference  between  the  albuminoids  of  the  two 
classes  is  simply  dependent  on  the  presence  or  absence 
of  the  phosphates;  but  the  chemistry  of  these  bodies  is 
only  in  its  infancy,  and  it  would  be  premature  to  offer  an 
opinion  at  the  present  time.  Besides  casein,  or  a  similar 
body,  there  exists  in  all  milks  a  second  albuminoid  called 
albumin ;  this  differs  from  casein  by  not  being  precipitated 
by  acid,  and  by  being  coagulated  by  heat.  Other  albu- 
minoids have  been  described  in  milk,  but  many  of  them 
are  only  decomposition  products  of  casein  or  albumin, 
which  were  formed  during  the  process  adopted  for  the 
removal  of  the  other  albuminoids.  .  .  . 

'  The  sugar  in  milk  is  of  a  peculiar  nature;  that  of 
cow's  milk  is  called  "lactose,"  or,  more  commonly,  sugar 
of  milk.  It  is  generally  assumed  that  all  milks  contain 
the  same  sugar,  but  of  this  there  is  some  doubt.  .  .  . 

"  The  sugar  of  the  milk  of  the  mare  has  the  property 
of  easily  undergoing  alcoholic  fermentation,  a  property 
not  possessed  by  lactose.  According  to  the  experiments 
of  Carter  and  the  author,  the  sugar  of  human  milk  is  not 
identical  with  that  of  the  milk  of  the  cow"  (Richmond). 

"  The  nitrogenous  constituents  of  milk  are  very  un- 


MILK    OF   DIFFERENT   ANIMALS.  45 

stable  compounds  and  their  study  presents  many  and  great 
difficulties;  as  a  result  we  find  that  no  two  scientists  who 
have  made  a  special  study  of  these  compounds  agree  as  to 
their  properties,  aside  from  those  of  casein  and  albumin, 
or  their  relation  to  the  nitrogenous  substances  found  else- 
where in  the  animal  body  "   .  .  .  (Farrington  and  Woll). 

"  The  milk  fat  has  rather  variable  specific  gravity, 
which  according  to  Bohr  is  0.949-0.996  at  -+-  150  C.  The 
milk  fat,  which  is  obtained  under  the  name  of  butter, 
consists  in  great  part  of  the  neutral  fats  palmitin,  olein, 
and  stearin.  Besides  these  it  contains,  as  triglycerides, 
myristic  acid,  small  quantities  of  butyric  acid  and  cafij'oic 
acid,  traces  of  caprylic  acid,  capric  acid,  lauric  acid,  and 
arachidic  acids.  .  .  .  Milk  fat  also  contains  a  small  quan- 
tity of  lecithin  and  cholesterin,  also  a  yellow  coloring 
matter.  .  .  . 

"  The  milk  plasma,  or  that  fluid  in  which  the  fat 
globules  are  suspended,  contains  several  albuminous 
bodies,  casein,  lactoglobulin,  and  lactalbumin,  and  a  little 
opalisin,  and  two  carbohydrates,  of  which  only  one,  the 
milk  sugar,  is  of  great  importance.  The  milk  plasma  also 
contains  extractive  bodies,  traces  of  urea,  creatin,  crea- 
tinine hypoxanthin  (?),  lecithin,  cholesterin,  citric  acid 
(Soxhlet  and  Henkel),  and  lastly  also  mineral  bodies  and 
gases"  (Hammarsten  on  cow's  milk). 

It  will  be  readily  seen  that  an  analysis  of  milk  that 
took  into  consideration  all  its  minor  ingredients  would  be 
an  exceedingly  complex  process  and  to  a  certain  extent  a 
needless  one ;  as  a  matter  of  fact  there  has  never  been  a 
process  of  complete  analysis  of  milk  worked  out. 

The  usual  method  of  analysis  is  to  evaporate  a  speci- 


46  INFANT   FEEDING. 

men  of  milk  to  dryness  and  call  its  weight  total  solids. 
What  ether  will  extract  from  "  total  solids  "  is  called  fat, 
although  the  lecithin  is  also  included.  The  total  nitrogen 
in  the  milk  is  determined  and  its  weight  multiplied  by  6.25 
(8)  and  called  pi'oteid.  In  this  proteid  is  again  included 
the  lecithin  as  it  contains  a  little  nitrogen.  A  portion  of 
the  total  solids  is  burned  and  the  weight  of  the  ash  in  the 
milk  is  calculated  as  mineral  matter.  The  weights  of 
water,  fat,  proteid  and  mineral  matter are  added  together 
and  subtracted  from  the  weight  of  the  milk  and  the  differ- 
ence called  carbohydrates  or  sugar.  This  method  is  not 
exact,  but  answers  all  practical  purposes  in  ordinary 
methods  of  calculating  food  values. 

Methods  of  determining  casein  and  albumin  in  milk 
consist  of  adding  acid  which  precipitates  the  casein  but 
not  the  albumin ;  the  casein  is  removed  by  filtration  and 
the  filtrate  is  boiled,  which  precipitates  albumin;  the 
nitrogen  in  each  is  determined  and  multiplied  by  6.25, 
When  the  weights  of  the  casein  and  albumin  so  deter- 
mined are  added  together  there  is  not  as  much  total  pro- 
teid as  when  the  nitrogen  in  the  whole  milk  is  determined 
and  multiplied  by  6.25. 

According  to  A.  Winter  Blyth,  an  English  authority 
on  food,  the  casein  of  woman's,  mare's,  and  ass'  milk  sep- 
arates only  with  great  difficulty,  and  then  not  completely, 
upon  the  addition  of  acids.  This  may  and  probably  does 
account  for  the  small  quantity  of  casein  reported  in  wom- 
an's milk  by  some  chemists  and  the  larger  quantity  ob- 
tained by  others  who  employed  different  methods  of 
analysis.  This  subiect  will  be  alluded  to  in  another 
place  (145). 


MILK   OF   DIFFERENT  ANIMALS. 


47 


No  method  of  quantitatively  determining  the  sugar  in 
milk  has  been  devised.  It  is  either  determined  "by  dif- 
ference," or  rotation  of  a  ray  of  polarized  light,  or  by  the 
reduction  of  alkaline  copper  solution.  The  quantity  of 
sugar  present  in  a  specimen  of  milk  varies  slightly  with 
the  method  of  determining  it. 

29.  The  composition  of  any  kind  of  milk  varies  a 
great  deal  and  it  is  customary  to  speak  of  average  milk. 
The  composition  of  average  milk  is  determined  by  adding 
together  a  great  many  analyses  of  milk  and  dividing  the 
sum  by  the  number  of  analyses.  It  may  be  that  the  re- 
sulting composition  of  milk  may  have  never  been  actually 
met  with.  In  speaking  of  woman's  milk  Hammarsten 
says:  "  Even  after  those  differences  are  eliminated  which 
depend  on  the  imperfect  analytical  methods  employed, 
the  quantitative  co7nposiiion  of  woman's  milk  is  variable 
to  such  an  extent  that  it  is  impossible  to  give  any  average 
results  "  ;  and  of  the  milk  of  other  animals, — "  To  illustrate 
the  composition  of  the  milk  of  other  animals  the  follow- 
ing figures,  the  compilation  of  Koenig,  are  given.  As  the 
milk  of  each  kind  of  animal  may  have  a  variable  com- 
position, these  figures  should  be  considered  only  as  ex- 
amples of  the  composition  of  milk  of  various  kinds:" 


Milk  of  the— 

Water. 

Solids. 

Proteids. 

Fat. 

Sugar. 

Salts. 

Dog 

75-44 
81.63 
86.91 
83.50 
87.17 
90.06 
90.00 

24.56 

18.37 
I3.O9 
16.50 
12.83 

9-94 
10.00 

9.9I 
9.08 
3.69 
5-74 
3-55 
1.89 
2.10 

9-57 
3-33 
4.09 
6.14 

3-69 
1.09 
1.30 

3-^9 

4.91 

4-45 
3-96 

4.88 
6.65 
6.30 

O   71 

Cat 

5S 
86 

Goat   

Sheep 

66 

Cow 

7i 
31 

Ass 

30 

From  the  analytical  figures  just  given  it  might  readily 
be  inferred  that  the  great  difference  between  milk  of  all 


48  INFANT   FEEDING. 

animals  lay  in  the  different  percentages  of  water,  proteids, 
fat,  sugar,  and  salts,  but  a  glance  at  the  following  analyses 
of  cheeses  made  from  milk  with  which  all  are  familiar 
will  show  what  a  grave  error  such  a  conclusion  would  be 
if  applied  to  cheese : 


Water. 


Proteids. 


Ordinary  cheese  (made  of  cow's  milk)  .  . 
Roquefort  cheese  (made  of  sheep's  milk) 


27.20 
26.50 


32.05 
52.30 


36.60 
32.90 


4.15 
4.4 


30.  Chemists  have  recognized  that  for  anything  but 
comparison  of  potential  food  values,  analyses  of  milk  are 
valueless,  and  have  classified  milks  according  to  their 
curding  properties. 

All  milks  contain  at  least  two  forms  of  protein:  casein, 
or,  as  it  is  called  by  some  writers,  caseinogen,  and  albumin, 
while  some  milks  contain  a  large  proportion  of  other 
forms  of  protein. 

Casein  of  cow's  milk  is  easily  precipitated  by  cold 
dilute  acids,  while  albumin  is  not.  The  curds  of  sour 
milk  consist  principally  of  precipitated  casein,  If  an 
alkali  is  added  to  neutralize  the  acidity  of  sour  milk  the 
casein  assumes  its  original  form.  However,  the  precipi- 
tation, or  curding  of  milk,  by  the  addition  of  acids  is  not 
the  physiological  curding  of  milk.  In  the  stomach  of 
animals  is  found  an  enzyme — rennet — which  clots  milk 
very  much  as  blood  is  clotted,  and  the  character  of  this 
clot  depends  on  the  kind  of  milk  that  is  used. 

31.  The  clotting  of  milk  by  rennet  is  an  entirely  differ- 
ent process  from  the  precipitating  of  casein  by  acids  or  the 
souring  of  milk.  Cow's  milk  is  changed  by  rennet  into  a 
solid,  which  shrinks    into  a  leathery,  stringy  mass  that 


MILK    OF   DIFFERENT   ANIMALS. 


49 


contains  the  fat  of  the  milk  embedded  in  the  meshes  of 
the  curd.  The  albumin  and  other  protein  bodies  and  the 
sugar  of  the  milk  are  squeezed  out  as  "  whey."  Horse's 
and  ass'  milk  form  a  very  soft,  gelatinous  curd  with  ren- 
net, and  woman's  milk  forms  finely  divided  curds. 

Even  after  the  milks  are  classified  according  to  their 
curding  properties  there  are  great  differences  in  the  com- 
position of  the  milks  which  need  to  be  explained.  Now, 
if  instead  of  making  the  chemical  analyses  or  curding 
properties  of  the  milks  the  bases  of  comparison,  the  milks 
are  classified  according  to  the  natural  order  of  the  animals 
producing  them,  the  reason  for  the  wide  differences  in 
milks  will  appear,  and  each  milk  will  be  seen  to  be  specially 
adapted  in  composition  and  curding  properties  to  the  rate 
of  growth  and  digestive  system  of  the  young  animal  it 
was  intended  to  nourish  (Chapter  IV.). 


Types  of  milk. 

'S 

Curds. 

a  0 

V 

-c  a 

'a)    ^ 
?    U 

a. 

Attains 

puberty  in 

months. 

Carnivorous 

Dog. 

Sheep 
Goat. 
Cow. 

Mare. 
Ass. 

? 

75-44 

83.50 
86.91 

87.17 

90.06 
90.00 

88.20 

9-57 

6.14 
4.09 
3-69 

1.09 
1.30 

3-30 

3-19 
3-96 

4-45 

4.88 

6.65 
6.30 

6.80 

9.91 

5-74 
3-69 

3-55 

1.89 
2. 10 

1.50 

0-73 
.66 

% 

■31 

•30 

.20 

6-8 

(Stomach  60  to  So  per 
cent     of     digestive 
tract.) 

Ruminant } 

(Stomach  70  per  cent 
of  digestive  tract.) 

(Intestine  90  per  cent 
of  digestive  tract.) 
Human 

Solid 
Solid 
Solid 

Gelatinous 
Gelatinous 

Flocculent 

6-8 
6-8 

S-12 

iS 
iS 

Myrs. 

(Stomach  20  per  cent 
of  digestive  tract.) 

It  should  be  remembered  that  these  milks  vary  some- 
what in  composition.  (See  32  A,  for  separate  analysis  of 
proteids.) 


5o  INFANT   FEEDING. 

It  will  be  noticed  that  the  milk  of  carnivorous  animals 
is  exceedingly  rich  in  proteids ;  that  the  milk  of  herbivor- 
ous animals,  whose  digestion  is  principally  gastric,  forms 
•solid  curds  which  cannot  easily  leave  the  stomach ;  that 
the  milk  of  herbivorous  animals,  whose  digestion  is  prin- 
cipally intestinal,  forms  gelatinous  curds  which  easily 
leave  the  stomach  and  pass  into  the  intestine;  and  that 
woman's  milk,  which  was  intended  for  a  digestive  system 
in  which  the  gastric  digestion  is  more  than  that  of  the 
horse  or  ass,  but  not  so  great  as  that  of  the  cow  or  goat, 
curds  in  flakes  which  stand  between  the  other  two  types 
of  curds. 

'  It  is  also  remarkable  how  close  to  each  other  in  type 
of  composition  the  milks  of  different  animals  of  the  same 
class  appear  to  be,  and  what  a  close  relation  there  is  be- 
tween the  composition  of  the  milk  and  the  rate  of  growth 
of  the  animal.  It  may  be  pointed  out  that  the  fat  and 
proteid  in  ewe's  milk  are  much  greater  in  quantity  than 
in  goat's  milk  and  greater  in  goat's  milk  than  in  cow's 
milk.  At  first  sight  there  appears  to  be  no  reason  for 
this,  but  there  is.  Sheep  produce  wool  and  goats  produce 
hair  which  are  made  up  of  protein  substance  and  fat. 
Over  forty  per  cent  of  the  weight  of  raw  wool  is  of  a 
fatty  nature  and  this  fat  is  found  not  in  the  wool  fibre 
alone  but  mostly  on  it.  It  is  the  familiar  lanolin  or  wool  fat. 
Hair  does  not  have  much  fat  on  it  and  goat's  milk  does  not 
contain  anything  like  the  same  quantity  of  fat  as  sheep's 
milk. 

There  is  an  apparent  discrepancy  between  the  com- 
position of  cow's  milk  and  mare's  milk  and  the  rate  of 
development  of   their  young.     It  must  be  remembered 


MILK   OF   DIFFERENT   ANIMALS.  51 

that  cows  have  been  bred  for  years  for  the  purpose  of 
producing  milk,  and  those  animals  that  did  not  produce 
rich  milk  have  been  rejected.  The  ordinary  common 
stock  of  cows  does  not  produce  milk  containing  fat  3.69, 
proteids  3.55  per  cent,  as  shown  in  the  analysis,  but  nearer 
fat  three  per  cent  and  proteids  three  per  cent.  The  dairy 
laws  in  most  of  the  States  call  for  only  three  per  cent  of  fat 
in  milk.  Horses  and  asses  have  not  been  bred  so  as  to 
produce  rich  milk  as  have  cows.  When  these  facts  are 
taken  into  consideration,  the  apparent  discrepancy  dis- 
appears. 

32.  One  of  the  great  differences  between  woman's  milk 
and  other  milks,  which  is  well  known,  but  which  is  not 
shown  in  the  analyses,  is  that  woman's  milk  is  richer  in 
lecithin,  which  forms  a  large  part  of  the  brain  and  nerves. 
Within  half  an  hour  after  birth  a  calf,  lamb,  kid,  or  colt  can 
stand,  and  in  a  day  or  two  runs  around  and  sees,  hears, 
and  smells  about  as  well  as  its  mother.  In  other  words,  it 
is  born  with  a  fully  developed  nervous  system.  A  baby  is 
very  different  in  this  respect,  and  it  needs  material  for 
building  up  its  nervous  system,  and  this  is  found  abun- 
dantly in  woman's  milk,  but  not  so  much  in  other 
milks. 

32  A.  In  all  milks  there  is  greater  or  less  quantity  of 
soluble  proteid  generally  called  albumin,  although  not 
nearly  all  albumin,  which  is  not  retained  in  the  curd,  but 
which  separates  with  the  carbohydrates  in  the  whey  (31). 
This  soluble  proteid  is  readily  absorbed  from  the  digestive 
tract.  It  was  shown  that  during  digestion  there  was  a  slight 
increase  in  proteid  and  a  large  increase  in  carbohydrate 
metabolism  (27).     The  first  step  in  the  digestion  of  milk,  it 


52  INFANT   FEEDING. 

will  be  seen,  is  a  separation  of  easily  absorbed  proteid  and 
carbohydrate,  for  which  there  is  a  great  demand  during 
digestion,  from  the  casein  and  fat,  which  require  more 
digestion  and  which  are  stored  away  in  the  growing  ani- 
mal as  fat  and  muscle;  and  in  another  place  it  will  be 
shown  that  the  fat  of  milk  is  mostly  secreted  at  the  latter 
part  of  a  suckling  or  milking  (36). 

32  B.  The  quantity  and  character  of  the  soluble  proteids 
of  milk  are  of  considerable  interest  in  the  comparison  of 
milks.  In  1897  Babcock  and  Russell  discovered  enzymes 
in  milk  which  would  digest  its  proteids  in  time  if  the 
bacteria  present  were  destroyed  by  means  other  than  heat, 
which  destroyed  the  enzymes.  To  prove  that  the  changes 
in  the  proteids  of  the  milk  were  due  to  these  enzymes, 
some  very  carefully  conducted  experiments  and  analyses 
were  made. 

The  casein  and  albumin  were  removed  from  milk  by 
heating  with  acetic  acid  and  filtering.  The  character  of 
the  remaining  nitrogenous  compounds  was  then  carefully 
investigated,  and  they  were  considered  to  be  principally 
albumoses  and  peptones  (11).  The  milks  were  set  aside, 
and  from  time  to  time  portions  were  analyzed  to  detect  the 
rapidity  of  the  digestive  process  which  was  found  to  be 
slow,  months  being  required  before  it  was  half  completed. 

While  the  discovery  of  the  presence  of  these  enzymes 
in  milk  has  no  practical  significance  in  infant  feeding  the 
analyses  made  in  this  connection  are  of  the  greatest 
value. 

In  the  following  analyses  by  Babcock,  Russell  and 
Vivian  only  the  cow's  and  goat's  milk  were  the  mixed 
secretion  of  several  animals.     In  another  place  (38)  will 


MILK    OF   DIFFERENT   ANIMALS. 


53 


be    found   many   complete  analyses    of    the    proteids  of 
cow's  milk. 


Date. 


December  4th,  1897. 
December  4th,  1897. 
December  4th,  1897. 
December  4th,  1897. 
December  29th,  1897. 
December  13th,  1897. 
February  1st,  1898.  . 

March  8th,  1898 

May  2d,  1898 

June  23d,  1898 

July  1st,  1898 

February  21st,  1898. 

April  20th,  1898 

April  28th,  1898 

December  29th,  1898 
February  21st,  1898. 
March  8th,  1898 


Kind  of  milk. 


Sheep  

Sheep  

Sheep  

Sheep  

Sheep  

Human  1  ?  .  . 
uman  |  =  g  . . 
Human  !  3  «.  .  . 
Human  j  §  * 
Human  |  3  ■£  .,. 
Human  J      7   ■  ■ 

Goat 

Pig 

Pig 

Mare 

Burro 

Half-bred  buffalo 
Cow  


3  u 

Sol.  N. 
Per  cent. 

0.  76 

0.09 

•71 

.  IO 

.60 

.IO 

.76 

.09 

.80 

.  IO 

.28 

.  IO 

.28 

.10   > 

.27 

.  10 

.27 

.09 

.28 

.10 

.27 

.  10 

.78 

.06 

•72 

•  17 

.70 

.16 

.28 

.09 

•25 

.10 

.48 

.04 

•51 

.04 

yr  X6.25  = 
(by 
author) 


r_ 

"a 
0 
H 

■c  c 

4-75 

4 

43 

3 

75 

4 

75 

5 

00 

1 

75 

\    1 

75 

1 

68 

1 

68 

1 

75 

1 

68 

4 

87 

4 

5i 

4 

37 

1 

75 

1 

54 

3 

00 

I  3 

18 

r-    1>    0) 

a  a  <j 

in 


0.58 
.62 
.62 
.56 
.62 
.62 
.62 
.62 
.56 
.62 
.62 

•37 
1.06 
1. 00 
.56 
.62 
•  25 
■25 


It  will  not  be  difficult  to  see  that  the  character  of  the 
proteids  of  milk  cannot  be  told  by  the  usual  chemical 
analysis ;  that  with  improved  methods  of  analyses  different 
results  are  obtained,  and  that  all  young  animals  are  not 
on  a  dead  level  when  they  are  on  a  milk  diet;  also  that  it 
would  be  irrational  to  expect  by  a  simple  adjustment  of 
percentages  of  fat,  sugar,  and  proteids  to  make  milks 
interchangeable,  even  from  a  chemical  standpoint. 


CHAPTER    IX. 

SUMMARY. 

33.  In  the  preceding  chapters  it  was  shown:  (1)  That 
all  animals  are  alike  in  the  chemical  processes  that  take 
place  within  their  organisms  during  starvation,  and  that  the 
administration  of  digestible  fat,  proteids,  or  carbohydrates 
singly  produces  the  same  result  in  all  kinds  of  animals. 

(2)  While  chemically  there  seems  to  be  no  difference 
.between  the  different  forms  of  animal  life,  physiologically 
there  are  vast  differences,  and  these  differences  seem 
to  be  closely  related  to  the  food  supply,  all  the  organs  and 
parts  of  the  body  of  a  particular  kind  of  animal  being 
adapted  to  enable  it  to  secure  and  digest  its  natural  food. 

(3)  In  the  case  of  young  animals  which  take  milk  it  was 
shown  that  not  only  does  the  milk  of  different  species  of 
animals  contain  practically  the  same  food  elements  in 
varying  proportions  and  forms  suited  to  the  needs  of  each 
particular  species,  but  that  the  milks  possess  different 
curding  properties  that  make  them  particularly  suitable 
to  their  respective  digestive  tracts,  and  that  the  process 
and  order  of  digestion  in  the  young  animal  are  practically 
the  same  as  those  of  the  parent. 

(4)  It  has  also  been  shown  that  while  the  chemical 
composition  of  milks  varies  greatly,  there  is  a  type  of  com- 
position for  each  distinct  class  of  animals,  also  that  the 
variations  within  these  types  are  considerable ;  but  that 


SUMMARY.  55 

in  spite  of  these  variations,  each  distinct  type  of  milk  has 
certain  physiological  properties  that  do  not  vary  with  the 
change  in  chemical  composition  or  concentration  of  the 
milk.  For  example,  poor  or  diluted  cow's  milk  has  the 
same  curding  properties  as  the  rich  milk  of  cows.  (5) 
That  the  selection  of  a  food  for  any  animal  cannot  safely 
be  made  upon  a  chemical  analysis  only,  but  by  the  aid  of 
a  digestive  test.  (6)  That  some  forms  of  proteid,  even 
when  digested,  will  not  produce  a  healthy  tissue,  and  that 
there  are  certain  combinations  of  the  various  food  prin- 
ciples or  elements  that  must  be  made  to  suit  each  class  of 
animals.-  As  the  chemistry  of  the  animal  tissues,  ingredi- 
ents of  milk,  and  different  foods  is  only  in  its  infancy,  and 
the  functions  of  all  the  food  elements  are  not  thoroughly 
understood,  it  is  useless  to  attack  the  problem  of  artificial 
infant  feeding  from  the  standpoint  of  chemistry  alone,  al- 
though a  knowledge  of  food  chemistry  is  of  great  assist- 
ance. What  is  needed  is  a  knowledge  of  the  substances 
that  have  proved  to  be  able  to  support  life  and  produce 
healthy  tissue ;  how  to  combine  and  to  adapt  them  to  suit 
the  needs  and  digestive  system  of  the  infant ;  the  indica- 
tions of  malnutrition  and  faulty  digestion,  and  how  to 
spare  tissue  waste  in  disease  by  an  alteration  of  diet. 

In  the  following  chapters  the  production  and  properties 
of  raw  food  materials  will  be  taken  up  and  then  the  prac- 
tical problems  of  infant  feeding. 


PART   II 


CHAPTER    X. 

COW'S   MILK. 

34.  Colostrum. — When  the  calf  is  born  its  digestive  sys- 
tem has  never  been  used  and  the  cow's  udder  secretes 
a  substance  entirely  different  from  normal  milk,  called 
colostrum,  which  seems  to  be  designed  to  educate  the  calf's 
digestive  system  to  digest  food.  Colostrum  is  composed 
of  fat,  sugar,  proteids,  mineral  matter,  and  water,  as  is 
normal  milk,  but  the  character  of  the  proteids  and  sugar 
is  different  from  that  of  normal  milk.  The  proteids  of 
colostrum  consist  largely  of  albumins  and  globulins,  and 
also  albumoses  and  peptones,  which  are  easily  assimi- 
lated, and  the  sugar  is  said  to  be  dextrose — the  sugar 
found  in  the  blood  and  not  the  milk  sugar  which  is  found 
in  cow's  milk. 

The  character  of  the  udder  secretion  gradually  changes, 
the  albumins  and  globulins  being  replaced  by  casein  and 
the  dextrose  by  milk  sugar.  The  albumins  and  globulins 
of  colostrum  will  coagulate  upon  boiling  just  as  does  the 
white  of  egg.  To  determine  when  the  udder  secretion 
has  become  normal  milk  it  is  boiled  and  if  it  does  not 
coagulate  it  is  considered  fit  to  be  used  as  milk.  The 
time  that  elapses  between  the  birth  of  the  calf  and  the 
secretion  of  normal  milk  varies,  sometimes  being  from 
five  to  seven  days  and  again  as  long  as  twenty-one 
days. 


6o 


INFANT   FEEDING. 


The  following  analyses  made  at  the  Vermont  Ex- 
perient  Station  will  give  an  idea  of  the  composition  of 
colostrum : 


Total  solids. 
Per  cent. 

Fat. 
Per  cent. 

Sugar. 
Per  cent. 

Casein  and 
albumin. 
Per  cent. 

Ash. 
PeT  cent. 

19-37 
14-33 
12.98 
13.92 

13-52 

3-86 
2.92 

2.58 

3-7i 
4.60 

2.40 
3- 60 
4.16 
4.28 
5.00 

II.44 
6.49 
5-OI 
4.71 
3-34 

I.67 

i-33 
1.23 
1.24 

Three  weeks  after  calving.  . 

.58 

35.  Constituents  of  Cow's  Milk. — In  a  broad  way  cow's 
milk  is  composed  of  fat,  sugar,  proteids,  mineral  matter, 
and  water.  Blood,  pus,  and  epithelium  may  be  present 
under  certain  conditions.  The  fat  is  not  a  single  body 
but  a  mixture  of  various  fats  (28),  which  change  somewhat 
in  character,  depending  on  the  period  of  lactation  and  the 
character  of  the  cow's  food.  Cotton  seed  fed  to  cows 
makes  a  hard  milk  fat;  linseed  meal  makes  a  soft  fat. 
The  fat  is  suspended  in  the  milk  serum  in  fine  globules, 
the  size  of  which  varies  with  the  breed  of  cows  and  also 
in  different  portions  of  a  milking  (36). 

There  are  two  carbohydrates  in  cow's  milk,  the  prin- 
cipal one  being  lactose,  the  common  milk  sugar. 

The  proteids  of  cow's  milk  as  far  as  known  are  com- 
posed of  casein  (by  some  authors  called  caseinogen),  albu- 
min, albumoses,  peptones,  and  S torch's  mucoid  proteid, 
which  has  the  property  of  swelling  up  under  the  action  of 
alkalies  (45). 

The  mineral  matter  of  milk  is  not  thoroughly  under- 
stood, but  the  following  analysis  by  Richmond  tells  about 
all  that  is  known  of  it. 

"  The  ash  does  not  truly  represent  the  mineral  con- 


COW'S    MILK.  61 

stituents  of  milk.      The  average  composition  of  the  ash 
of  milk  is: 

Per  cent. 

Lime ..>...,...  20. 27 

Magnesia ■ ...  2.80 

Potash 28.  71 

Soda 6.67 

Phosphoric  acid 29. 33 

Chlorine   , 14. 00 

Carbonic  acid    .97 

Sulphuric  acid , Trace. 

Ferric  oxide,  etc , , ,  .  .  .40 

103.15 
Less  0  +  CI , 3.15 

100.00  " 

Lecithin  found  dissolved  in  the  fat,  citric  acid,  urea, 
and  cholesterin  are  minor  constituents  of  cow's  milk. 
Certain  enzymes  are  also  found  in  milk,  but  these  have 
practically  no  importance  except  in  the  manufacture  of 
various  kinds  of  cheese.  These  enzymes  are  mentioned 
in  another  place  (32). 

36.  Composition  of  Cow's  Milk. — The  composition  of 
cow's  milk  varies  greatly,  and  it  is  impossible  to  give  a  rep- 
resentative analysis  that  will  do  more  than  show  what  the 
average  composition  of  milk  would  be  during  a  long  period 
if  the  cows  gave  the  same  milk  each  day  and  at  each 
milking.  This  kind  of  analysis  is  useful  only  in  showing 
the  amount  of  food  material  cows  produce  during  a  stated 
period. 

One  Cow's  Milk. — The  milk  of  individual  cows  shows 
great  and  sudden  variations  in  composition,  and  it  is  for 
this  reason  that  the  mixed  milk  of  a  herd  of  cows  is  better 
for  general  use  than  one  cow's  milk.  While  there  are 
great  differences  in  composition  between  the  mixed  milks 
of  different  herds  of  cows,  there  are  not  apt  to  be  great 


62 


INFANT   FEEDING. 


and  sudden  variations,  and  with  care  the  milk  can  be  kept 
very  uniform  in  composition. 

The  changes  in  composition  in  one  cow's  milk  are 
caused  by  various  influences,  as  sudden  change  of  the 
character  of  the  food,  fright,  unfamiliar  surroundings,  and 
irregular  intervals  between  milkings.  Gradual  change  in 
the  character  of  the  food,  running  from  low  proteid  to 
high  proteid  and  vice  versa,  low  fat  to  high  fat  and  vice 
versa,  and  high  carbohydrates  and  low  proteids  cause  no 
perceptible  change  in  the  composition  of  the  milk.  It 
is  the  opinion  of  all  investigators  that  the  quantity  and 
quality  of  the  milk  depend  on  the  cow,  and  that  there  is 
no  method  of  feeding  that  will  cause  a  particular  cow  to 
change  the  natural  quality  and  quantity  of  milk  secreted, 
except  for  a  few  days,  when  there  will  be  a  return  to  the 
normal  of  each  cow. 

The  following  analyses  of  individual  cow's  milk  show: 
(i)  The  variation  in  quantity  of  fat  and  size  of  fat  globules 
in  different  portions  of  a  milking — the  solids  not  fat 
seem  to  change  little;  C2)  the  variations  in  composition 
and  yield  of  milk  during  a  lactation  period ;  and  (3)  the 
effect  of  irregular  hours  of  milking.  These  analyses  are 
suggestive  of  changes  and  conditions  affecting  the  secre- 
tion and  composition  of  breast  milk. 

(1)  Fractional  Milkings.  Boussingault  (quoted  by 
Richmond)  reports : 


First 
portion. 
Per  cent. 

Second 
portion. 
Per  cent. 

Third 

portion. 
Per  cent. 

Fourth 
portion. 
Per  cent. 

Fifth 

portion. 
Per  cent. 

Sixth 
portion. 
Per  cent. 

IO.47 
I.  70 
3-77 

IO.75 
I.76 
S.99 

IO.85 
2.IO 

S.75 

II.23 

2-54 
8.69 

II.63 
3-14 
8.49 

12.67 
4.08 

Fat   

8-59 

COW'S   MILK. 


63 


Collier  at  the  New  York  (Geneva)  Experiment  Station 
obtained  the  following  figures: 


First  Cow — 
First 
Second 

Third 

Fourth 

Fifth 

Sixth 

Seventh 

Eighth 

Ninth 

Tenth 

Eleventh 

Twelfth 

Thirteenth 


pint 


Fat. 
Per  cent. 

0.3 

•  -3 

•  -4 

•  -7 
•7 

.    1. 12 
1.7 
2.2 
2.55 

•  3-0 

•  3-35 

•  3-9 
4-95 


All  mixed 1 . 9 

Second  Cow — 

First        pint 

Second      "  

Third        "  

Fourth      " 

Fifth         ««  

Sixth         4*  

Seventh    "  

Eighth      "  , 

Ninth       "  

Tenth       *•  , 


All  mixed 2.77 

Third  Cow — 

First         pint 

Second       "     


Third 

Fourth 

Fifth 

Sixth 

Seventh 

Eighth 

Ninth 

Tenth 

Eleventh 


Relative  size  fat 
globules. 

36 

44 

93 

10S 

97 
133 
154 
174 
114 
147 
190 
194 
251 

129 


0.5 

123 

1. 1 

204 

i-3 

178 

1.8 

137 

2.4 

342 

3-4 

221 

4-45 

340 

5-o 

347 

5.o 

270 

6.25 

365 

218 


1.55 

337 

3-05 

367 

3-30 

338 

4.00 

476 

4.40 

323 

5- 00 

575 

6. 10 

565 

6.50 

833 

7.00 

722 

8.05 

725 

9.40 

644 

All  mixed 6.00 


659 


64 


INFANT   FEEDING. 


(2)  Variations  in  composition  and  yield  during  a  lac- 
tation period,  reported  by  Farrington. 

Holstein  Cow — 278  Samples. 


Daily  yield  in  pounds. 

Highest 37-0 

Lowest 1.7 

Average 21.7 


Solids  not  fats — per  cent. 

Highest 10.9 

Lowest 7-2 

8  times  below S.o 

24      "      above 9.0 

Short  Horn  Cow— 428  Samples— Sudden  Changes  not  Common. 


Fat — per  cent. 

Highest 6.6 

Lowest ...  1.5 

72  times  below 3.0 

25      "     above 4. 5 


Proteids — per  cent. 

Highest 4. 11 

Lowest 2.64 


Daily  yield  in  pounds — 

Highest 26.  5 

Lowest 3.5 

Average 14- 4 


Solids  not  fat — per  cent. 

Highest 11. 3 

Lowest 7. 2 

1 1  times  below 8.5 

7     "       above 10. 5 

Jersey  Cow — 614  Samples — Sudden  Changes  Common. 


Fat — per  cent. 

Highest 7.9 

Lowest 2.5 

17  times  below 3.0 

3S      "     above 4.5 


Proteids — per  cent. 

Highest 3.89 

Lowest 2.92 


Fat — per  cent. 

Highest 12.3 

Lowest 2.9 

5  times  below. 3.5 

25      "      above 7.0 

Proteids — per  cent. 

Highest 5.3 

Lowest 2.98 


Daily  yield  in  pounds — 

Highest 25.5 

Lowest 1.0 

Average 16. 4 

Solids  not  fat — per  cent. 

Highest. II. 7 

Lowest    7.6 

3  times  below S.o 

24       "     above to.  5 

(3)  Unequal  Intervals  between  Milkings.  The  shorter 
the  intervals  between  milkings  the  smaller  will  be  the 
yield  and  the  richer  the  milk.  Long  intervals  cause  large 
quantities  of  poor  milk.  It  is  for  this  reason  that  gener- 
ally in  summer,  morning  milk  is  richer  than  night  milk, 
and  in  winter,  night  milk  is  richer  than  morning  milk. 


COW'S   MILK. 


65 


Cows  are  milked  the  first  thing  in  the  morning  and  the 
last  thing  at  night  by  most  farmers.  In  summer  the  nights 
are  about  nine  hours  long,  and  in  winter  the  days  have 
about  this  same  length.  The  following  tests  made  at  the 
Delaware  Experiment  Station  illustrate  these  statements. 


Yield. 
Ounces. 

Fat. 
Per  cent. 

Total  solids. 
Per  cent. 

Milking  at  7  a.m 

154.6 
151. 0 
1S4.O 
112.  5 

4.63 
4-74 
4-36 
5-32 

14-25 
14-37 
14.53 
I5-36 

"         "   8  A.  M 

"    5  p-m 

Night  milk. 
Fat  — per  cent. 

Morning  milk. 
Fat — per  cent. 

July  24th , 

3-76 
4  sfi 

4-67 

February  5th 

37.  Curdijig  of  Milk. — The  curding  of  sour  milk,  so  fa- 
miliar to  every  one,  consists  of  a  precipitation  of  the  casein 
by  the  lactic  acid  developed  during  the  souring  process. 
Upon  neutralizing  the  acid  with  an  alkali  the  casein  goes 
back  into  its  original  condition.  The  curding  of  milk  in 
the  stomach  is  an  entirely  different  process  (6,  31).  It  is 
brought  about  by  the  action  of  rennet,  which  clots  the  ca- 
sein very  much  as  blood  is  clotted  by  the  enzyme  thrombase 
which  exists  in  the  blood.  The  milk  forms  a  solid  jelly 
when  acted  on  by  rennet,  which  soon  begins  to  contract, 
and  a  greenish-yellow  fluid  known  as  whey  exudes,  which 
contains  a  small  amount  of  fat,  the  soluble  proteids,  the 
sugars,  and  part  of  the  mineral  matter  of  the  milk.  A 
slightly  acid  condition  of  the  milk  greatly  favors  the  curd- 
ing or  clotting  of  milk  by  rennet.  When  the  conditions 
are  right  the  curd  shrinks  rapidly  and  forms  a  tough,  semi- 
fibrous  mass  that  contains  the  fat  in  its  meshes.  If  this 
5 


66  INFANT   FEEDING. 

curd  is  broken  into  small  particles  they  readily  unite  again 
into  a  solid  mass  if  allowed  to  remain  in  contact  with  each 
other;  but  if  the  particles  are  agitated  for  a  few  moments 
a  skin  or  membrane  forms  on  each,  which  prevents  their 
uniting.  The  casein  in  this  form  of  curd  is  changed 
chemically  and  cannot  be  put  back  into  its  original  form 
by  any  known  process. 

It  is  often  stated  that  cow's  milk  has  an  acid  reaction 
when  it  leaves  the  cow  or  in  its  fresh  state.  Acidity  of 
milk  is  never  estimated  directly,  but  by  the  use  of  some 
color  indicator.  Milk  that  is  neutral  to  litmus  is  usually 
quite  acid  to  phenolphthalein;  but  it  is  thought  that  this 
is  not  true  acidity,  but  the  effect  of  the  salts  found  in  the 
milk.  The  acidity  of  milk  that  aids  the  action  of  rennet 
is  true  acidity  and  is  shown  by  litmus.  An  interesting 
proof  that  the  acidity  to  phenolphthalein  is  not  true  acid- 
ity has  been  shown  by  Babcock,  Russell,  Vivian,  and 
Hastings.  They  found  that  pepsin,  which  digests  proteid 
only  in  the  presence  of  acid,  would  not  attack  the  proteids 
of  milk  that  was  acid  to  phenolphthalein  until  0.2  per 
cent.  HC1  was  added,  also  that  the  boiled  milk  would  not 
coagulate  with  rennet ;  but  it  did  so  at  once,  as  soon  as 
acidified. 

It  is  important  that  the  difference  between  the  acid 
curds  and  rennet  curds  of  milk  should  be  understood. 
Much  confusion  has  arisen  because  this  difference  was 
not  considered.  Series  of  tests  with  acid  curds  have  been 
used  as  bases  for  preparing  cow's  milk  for  infant  feeding, 
but,  as  under  physiological  or  rennet  curding,  entirely  dif- 
ferent results  are  obtained,  these  teachings,  based  on  acid 
curding  of  milk,  have  been  abandoned. 


COW'S   MILK.  67 

A  clear  conception  of  the  difference  between  the  acid 
curding  (precipitation  of  casein)  and  the  rennet  curding 
(clotting  of  cow's  milk)  can  be  quickly  obtained  by  per- 
forming the.  following  experiments,  preferably  in  small 
evaporating  dishes: 

1  st.  Dissolve  1  c.c.  of  hydrochloric  acid  in  99  c.c.  of 
water.  Add  this  gradually  to  60  c.c.  of  fresh  milk  that  is 
neutral  or  only  faintly  acid  to  litmus  paper  until  a  pre- 
cipitate forms,  and  note  how  many  cubic  centimetres  of 
the  dilute  acid  were  required  to  precipitate  the  casein. 
This  is  the  sour-milk  curd. 

2d.  To  60  c.c.  of  the  same  .milk  add  first  1  or  2  c.c. 
of  a  solution  of  rennet  made  from  the  commercial  liquid 
rennet  or  from  the  junket  tablets  sold  in  all  grocery  stores 
—one  tablet  to  30  c.c.  water — and  then  add  the  dilute 
hydrochloric  acid  until  a  precipitate  forms,  and  note  how 
many  cubic  centimetres  of  the  dilute  acid  were  required 
to  cause  the  precipitate  to  form.  Much  less  acid  will  be 
required  than  when  no  rennet  is  used.  Now  bring  the 
curded  milk  to  blood  heat  and  the  rennet  curd  will  begin 
to  shrink  and  after  a  few  minutes  will  become  tough  and 
fibrous  so  that  it  can  be  handled  without  breaking. 

If  this  experiment  is  performed,  using  20  c.c.  of  milk 
and  40  c.c.  of  water,  the  shrinking  is  more  pronounced. 
With  a  little  practice,  milk  diluted  ten  times  with  water 
can  be  curded  with  rennet  so  that  all  of  the  curd  will 
unite  into  one  small  piece.  Without  the  addition  of  the 
dilute  acid  the  curding  process  takes  more  time.  If  the 
casein  is  first  precipitated  by  the  acid  the  rennet  will  not 
cause  it  to  clot.  Occasionally  specimens  of  milk  will  be 
met  that  do  not  readily  form  a  curd  with  rennet. 


68  INFANT    FEEDING. 

38.  Mixed  Milks  and  Whey. — Market  milk  is  a  mixture 
of  the  secretion  of  many  cows,  and  varies  between  three 
and  five  per  cent  of  fat ;  but  the  milk  of  any  particular 
milkman  is  quite  uniform  from  day  to  day.  It  is  useless 
then  to  think  of  average  milk,  so  a  number  of  complete 
analyses  of  milks  within  the  normal  range  will  be  given. 
In  many  of  the  older  analyses  of  milk  the  total  proteids 
are  called  casein ;  in  other  analyses  the  total  proteids  and 
the  casein  have  been  determined,  and  the  difference  be- 
tween these  has  been  called  albumin.  In  some  more  re- 
cent analyses  the  proteids  other  than  casein  have  been 
determined,  but  there  is  as  yet  no  generally  accepted 
method  of  separating  these  proteids. 

As  the  relation  between  the  quantity  of  casein  and  so- 
called  albumin  of  milk  has  been  made  the  basis  of  a  system 
of  infant  feeding,  some  space  will  be  given  to  this  subject. 

It  has  been  pretty  generally  believed  and  accepted,  on 
the  authority  of  Koenig  and  Blyth,  that  there  is  a  quite 
constant  ratio  between  casein  and  albumin  of  cow's  milk, 
there  being  about  five  times  as  much  casein  as  albumin. 
Van  Slyke,  in  looking  over  a  large  number  of  analyses  of 
normal  milks  reported  by  different  analysts,  found  that 
the  ratio  between  casein  and  albumin  in  these  analyses 
was  as  high  as  ten  parts  of  casein  to  one  of  albumin,  and 
as  low  as  three  parts  of  casein  to  one  of  albumin.  He 
then  began  a  systematic  examination  of  milk  to  deter- 
mine the  ratio  between  casein  and  albumin,  if  there  was 
one.  This  test,  which  is  remarkable,  extended  over  a  pe- 
riod of  several  years ;  and  during  the  first  year  the  milk  of 
fifteen  hundred  cows  in  four  counties  of  New  York  State 
was  used  at  several  cheese  factories.     The  total  quantity 


COW'S    MILK. 


69 


of  milk  used  was  214,684  pounds,  and  106  analyses  were 
made  in  triplicate  to  exclude  any  chance  of  error.  His' 
conclusions  then  were:  "Our  results  show  that  the  rela- 
tion of  albumin  to  casein  is  a  very  variable  one  instead  of 
constant,  and  in  no  single  instance  did  any  sample  of  the 
mixed  normal  milk  contain  as  much  as  five  parts  of  casein 
for  one  of  albumin,  the  highest  being  4.9,  while  the  aver- 
age was  3.76  parts  casein  for  one  of  albumin." 

In  the  following  analyses  of  Van  Slyke,  the  casein  and 
albumin  (total  proteids),  and  casein  were  determined  direct- 
ly, and  the  water,  albumin,  sugar,  and  ash  indirectly.  These 
analyses  were  made  in  triplicate  both  for  the  milk  and  the 
whey,  and  are  exceedingly  useful  in  showing  the  range  of 
composition  of  mixed  milks  that  may  be  met  anywhere,  and 
the  composition  of  whey  made  from  a  particular  milk. 


Milk  . 
Whey. 

Milk 
Whey. 

Milk  . 
Whey 

Milk  . 
Whey 

Milk  . 
Whey- 
Milk  . 
Whey 

Milk 
Whey 

Milk 
Whey 

Milk- 
Whey 


a. 


88.40 
93-13 
87.81 
92.60 

87.97 
92.83 

87.94 
92.82 

S7-52 
92-93 
87.52 
93.02 

87.80 
93-27 

87-45 
93-Q4 

87.38 
93-05 


II.OO 

6.87 

I2.I9 

7.40 

12.03 

7-17 

12.06 

7.18 

12.48 

7.07 

12.48 
6.98 

12.  20 
6-73 

12.55 
6.96 

12.62 
6-95 


ffl.S   C 

-  5  u 


2.64 

.69 

2.72 

.71 

2.63 


3.20 

.88 

3-14 

.Si 

3-09 


S- 1 5 

.83 


3-15 
.86 


98 

0. 

06 

. 

03 

# 

97 

•43 

■47 

•5i 

•  44 

•47 

X  c  n        f 

-  -~   /        a; 

v  p  0-0  c 
v  5  £  22 


,66 

.66 

.60 

.6S 

77 

.67 

5S 

7i 

.68 


5-9i 

5.90 

6-37 
6.36. 

6.10 
6. 10 

6.06 
6. 12 

5-83 
5- 96 

5-84 
5-79 

5-56 
5-52 

5.80 
5.81 

5-82 
5-79 


INFANT    FEEDING. 


Milk  , 
Whey 

Milk, 
Whey 

Milk 
Whey 

Milk 
Whey 

Milk 
Whey 

Milk 
Whey 

Milk- 
Whey 

Milk 
Whey 

Milk- 
Whey 

Milk 
Whey 

Milk 
Whey 

Milk 
Whey. 

Milk 
Whey. 

Milk- 
Whey. 

Milk 
Whey, 

Milk- 
Whey. 

Milk 
Whey. 

Milk- 
Whey. 

Milk 
Whey. 

Milk 
Whey. 


a  u 

0—  ° 

a. 

87.46 

93-17 

12.54 
6.83 

87.41 
93.18 

12.59 
6.82 

87.54 

93- 19 

12.46 

6.81 

S7-34 
93.16 

12.66 

6.84 

87.41 

93-23 

12.59 

6.77 

87.29 
•  93- 10 

12.71 
6.90 

S7.00 
93.04 

13.00 
6.96 

86. 91 

93-17 

13.09 

6.83 

86.92 

93- IS 

13.08 
6.82 

86.  59 
93.04 

I3-4I 
6.96 

86.16 
92.50 

13.84 
7- 50 

36.53 
93.28 

13-47 
6.72 

86.61 
92.91 

13-39 
7.09 

86. 31 
93-  00 

13.69 

7.09 

86.54 
92.96 

I3-46 
7.04 

85.90 
92.94 

14.10 
7.06 

85. iS 
92.50 

14.82 

7.50 

35-37 
92.62 

14.63 

7-38 

85-13- 
92.56 

14.87 
7-44 

85.06 
92.  74 

14.94 
7.26 

£  =  a  c  2 


3-13 

-85 

3.06 

•S3 

3.08 
.82 

3.18 
.S6 

3-i3 

•S3 

3.22 

.38 

3-29 
.87 

3-45 
.87 

3-36 
.89 

3.4S 
.91 

3.38 
.89 

3.48 
■94 

3-44 
.90 

3-59 
■94 

3-46 
.88 

3.62 
•97 

3-93 
1  01 

3-99 
1.03 

4.00 
1.04 

3-S6 
1.04 


2 

•49 

.64 

2 

.48 

•  53 

2 

46 

62 

2 

53 

65 

2 

56 

.62 

2 

49 

73 

2 

68 

61 

2 

77 

68 

2 

68 

68 

2 

76 

•72 

2 

62 

76 

2 

75 

73 

2 

64 

80 

2 

90 

69 

2 

7i 

75 

3 

06 

56 

3- 

13 

80 

3- 

14 

S5 

3- 

18 

82 

3- 

10 

76 

5-71 
5-66 

5.78 
5.65 

5.58 
5  55 

=  .63 

5- 61 

5-51 

5o8 

5-54 
5.68 

5-71 
5-79 

5-59 
5-59 
5.62 

5-58 

5-73 
#5-7o 

6.26 

6.27 

5-74 
5.46 

5.65 
5.SS 

5-75 
5-71 

5.60 

5-76 

5-93 

5-75 

6.04 
6.18 

5.64 
6.04 

5-77 
6.06 

5-33 
5.86 


COW'S   MILK. 


7i 


In  a  series  of  analyses  made  in  another  year,  the  pro- 
teids  were  further  separated  and  the  range  for  the  year 
was:  Total  solids,  12.29  to  13.39  per  cent;  fat,  3.40  to 
4.10  per  cent;  casein,  2.19  to  2.26  per  cent;  albumin, 
0.28  to  0.38  per  cent ;  albumoses,  0.30  to  0.50  per  cent. 

Babcock  and  Russell  in  1897  published  the  following 
analyses  of  the  proteids  of  many  samples  of  cow's 
milk: 


M  5  C 

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•25 

56 

•45 

.04 

author) 

3 

50 

2.81 

•25 

•44 

57 

•43 

.05 

3 

56 

2.68 

•31 

•  57 

58 

•47 

.07 

3 

62 

2.94 

•43 

•25 

53 

.41 

.08 

3 

62 

2.56 

•50 

•55 

59 

.44 

.04 

3 

6S 

2-75 

•25 

.68 

60 

.46 

.04 

.70  J 

3 
4 

75 

2.87 

.25 

.63 

72 

.56 

50 

3-  50 

•44 

•56 

39.  Cream. — The  fat  globules  of  milk  being  much 
lighter  than  the  other  ingredients  of  the  milk  have  a  ten- 
dency to  rise  to  the  surface  if  the  milk  is  allowed  to 
remain  undisturbed  for  any  length  of  time.  The  separa- 
tion of  the  fat  from  the  other  ingredients  of  the  milk  is 
not  complete,  so  cream  is  a  mixture  of  milk  elements  in 
which  fat  greatly  predominates. 

4°-  Cream  Separating. — There  are  three  methods  of 
separating  cream  from  milk.  (1st)  The  shallow-pan  sys- 
tem in  which  the  milk  is  poured  into  wide,  shallow  pans; 
(2d)  the  deep-setting  system,  in  which  the  milk  is  put  into 
tall,  narrow  vessels,  and  allowed  to  stand;  and  (3d)  the 


72  INFANT   FEEDING. 

centrifugal  process  in  which  the  milk  is  run  through  a 
bowl  which  revolves  at  a  high  rate  of  speed. 

41.  Gravity  Cream. — Cream  that  is  allowed  to  rise 
naturally  and  is  then  skimmed  by  hand  is  called  gravity 
cream.  The  separation  of  cream  in  the  shallow-pan  sys- 
tem is  not  very  complete,  and  this  system  is  not  used 
much  in  producing  cream  for  market. 

Strange  to  say,  if  milk  is  put  into  tall  narrow  vessels 
and  placed  in  cold  water  at  450  F.,  the  cream  rises  quickly 
and  completely,  the  skim  milk  often  containing  not  over 
0.2  to  0.4  per  cent  of  fat.  This  system  is  well  illustrated 
by  bottled  milk,  on  which  the  layer  of  cream  can  usually 
be  plainly  seen. 

42.  Time  Required  for  Cream  to  Rise. — If  milk  is 
placed  in  cans  or  bottles  immediately  after  milking,  before 
it  has  had  time  to  cool,  the  separation  of  cream  is  rapid. 
At  the  end  of  four  hours  nearly  all  the  cream  that  will  rise 
will  have  risen ;  but  if  the  milk  has  been  stirred  and  cooled 
before  it  is  set  for  the  cream  to  rise,  the  separation  will  take 
many  hours  longer  and  will  not  then  be  as  complete  (132). 
Other  conditions  affecting  the  separation  of  cream  are 
the  size  of  the  fat  globules,  the  passing  of  milk  through 
a  centrifugal  machine  as  is  sometimes  done  to  remove 
dirt,  and  heating  the  milk.  The  smaller  the  fat  globules 
the  longer  time  is  required  for  the  cream  to  rise.  In  the 
milk  of  certain  breeds  of  cows  the  fat  globules  are  very 
small;  such  milk  does  not  cream  well.  In  rich  milks, 
containing  over  four  and  one-half  per  cent  of  fat,  the  fat 
globules  are  larger  and  creaming  is  rapid  and  complete 
(36).  Passing  milk  through  a  centrifugal  machine  breaks 
up  the  natural  arrangement  of  the  fat  globules ;  and  gravity 


COW'S   MILK. 


73 


cream  from  such  milk  separates  slowly  and  incompletely, 
is  very  thin  and  limpid,  and  apt  to  deceive  in  richness  one 
who  has  not  tested  it.      Such   cream,  containing   over 


Fig.  8. — Microscopic  Appearance  of  Normal  Milk.     (Babcock  and  Russell.)     Fat  globules  in 

clusters. 


Fig.  9. — Microscopic  Appearance  of  Centrifuged,  or  Heated  Milk.     (Babcock  and  Russell.)     Fat 

globules  not  in  clusters. 

twenty  per  cent  of  fat,  is  often  apparently  not  thicker 
than  rich  milk.  Heating  milk  also  prevents  its  creaming 
well. 

43.   Centrifugal  Cream. — The  first  centrifugal  cream 


74 


INFANT   FEEDING. 


separators  were  simple  buckets  of  milk  which  were  whirled 
until  the  cream  rose,  when  it  was  skimmed  by  hand.  Later 
a  circular  bowl  was  devised,  which  when  revolved  three 
thousand  to  five  thousand  times  a  minute  caused  a  rapid 
separation  of  cream.  The  milk  arranges  itself  into  several 
layers.  The  dirt  and  heavy  particles,  such  as  epithelium 
and  manure,  are  thrown  against  the  side  of  the  bowl ;  next 

u 


Fig.   io. — Centrifugal  Cream  Separator.     (Wing.)     a.  Inflowing  miik  ; 
6,  outflowing  skimmed  milk  ;  c,  outflowing  cream. 

comes  the  skim  milk,  and  then  the  cream  which  is  lightest 
is  nearest  the  centre  of  the  bowl.  A  clear  idea  of  the 
state  of  the  milk  in  a  separator  bowl  can  be  had  by  imagin- 
ing a  quart  bottle  of  milk  on  which  the  cream  has  risen 
being  laid  on  its  side  without  the  arrangement  of  the 
cream  being  disturbed.  The  bottom  of  the  bottle  with 
its  sediment  would  correspond  to  the  side  of  the  bowl 
and  the  mouth  of  the  bottle  to  the  centre  of  the  bowl. 


COW'S    MILK.  75 

Now  imagine  a  small  stream  flowing  from  the  layer  of 
cream  near  the  mouth  of  the  bottle  and  another  from  the 
skim  milk  near  the  bottom  of  the  bottle,  with  the  bottle 
kept  filled  all  the  time  by  a  fresh  supply  stream  of  milk 
that  separated  as  soon  as  it  entered  the  bottle  into  the 
layers  of  dirt,  skim  milk,  and  cream,  and  the  centrifugal 
cream  separator  will  be  understood. 

The  illustration  shows  a  simple  style  of  separator  bowl 
in  operation. 

The  length  of  time  the  milk  remains  in  the  bowl  of 
the  separator  can  be  regulated  and  the  cream  made  richer 
or  poorer  in  fat  accordingly.  The  shorter  the  time  the 
milk  is  in  the  bowl  the  poorer  the  cream  is  in  fat. 

44.  Separator  Slime. — After  a  quantity  of  milk  has 
been  passed  through  a  separator  there  is  found  sticking  to 
the  inside  of  the  bowl  what  is  known  as  separator  slime. 
Its  composition  is  variable,  but  it  generally  consists  of 
epithelium,  mucus,  pus,  blood,  dirt,  manure,  hair;  and  if 
the  milk  is  slightly  sour,  of  quantities  of  precipitated 
casein.  There  is  always  more  or  less  of  this  separator 
slime,  even  if  the  best  and  cleanest  milk  is  used.  It  is 
not  necessarily  filth,  although  when  obtained  from  dirty 
milk  it  contains  much  filth. 

45-  Difference  between  Gravity  and  Centrifugal  Cream. 
—When  milk  leaves  the  cow  the  fat  globules  are  free ;  but 
shortly  after  milking  they  form  themselves  into  little 
groups,  supposedly  under  the  action  of  a  substance  similar 
to  fibrin.  When  milk  is  passed  through  a  separator  or  is 
heated  for  that  matter,  this  arrangement  of  the  fat  globules 
is  broken  up  (43).  There  is  also  a  separation  of  the  pro- 
teids.     To  quote    Babcock   and    Russell:    "A   chemical 


?6  INFANT    FEEDING. 

analysis  of  fresh  separator  creams  showed  that  from  eigh- 
teen to  thirty-eight  per  cent  of  the  total  protein  was  present 
in  the  form  of  albumoses  and  peptones,"  while  they  found, 
on  an  average,  that  in  fresh  whole  milk  9.69  per  cent  of 
the  protein  was  albumoses  and  peptones.  Hence  there 
is  a  great  difference,  both  physical  and  chemical,  between 
gravity  and  centrifugal  creams;  and,  in  the  author's  opin- 
ion, gravity  cream  from  bottled  milk  is  to  be  preferred  for 
use  in  infant  feeding  on  the  principle  that  the  less  the 
milk  is  manipulated  and  the  ingredients  are  separated, 
the  better. 

In  butter-making  this  separation  of  proteids  and  change 
in  form  of  the  emulsion  of  the  fats  in  centrifugal  cream  is 
not  a  disadvantage,  for  butter  can  be  made  from  centrifugal 
cream  without  the  "ripening"  or  partial  souring  that 
gravity  cream  must  undergo  before  butter  can  be  made 
from  it.  For  many  commercial  purposes,  however,  cen- 
trifugal or  heated  (Pasteurized)  creams  cannot  be  used. 
Charlotte  russe  and  ice-cream  makers  and  cooks  insist  on 
having  gravity  creams  because  they  will  "  whip,"  while 
centrifugal  or  Pasteurized  creams  will  not  "  whip." 

Cream  Thickeners . — To  overcome  the  objections  thus 
inherent  in  centrifugal  cream,  Babcock  and  Russell  in- 
vented a  process  of  giving  "body"  to  creams,  which  con- 
sists of  adding  a  syrup  of  lime,  which  they  call  "  viscogen," 
to  the  centrifugal  or  Pasteurized  creams.  Syrup  of  lime 
can  be  had  at  any  drug  store  and  contains  six  and  one- 
half  per  cent  of  lime.  A  few  drops  of  this  syrup  of  lime 
will  cause  cream  or  milk  to  become  thick  and  viscid,  its 
action  being  on  the  mucoid  proteid  (35)  of  the  milk — the 
distinctive  property  of  mucin  being  that  of  forming  mu- 


COW'S   MILK.  77 

cilaginous,  stringy  solutions  when  acted  upon  by  a  trace 
of  alkali.  Any  one  having  much  to  do  with  milk  or  cream 
should  try  adding  syrup  of  lime  to  both  and  should  also 
taste  them  when  thickened.  The  taste  is  distinctive  but 
not  unpleasant. 

Another  method  of  thickening  cream  consists  of  add- 
ing solutions  of  gelatin.  Such  thickeners  are  sold  by 
dairy  supply  houses  under  different  names  (see  cream,  al- 
buminoid) (63). 

46.  Condensed  Milk. — There  are  two  distinct  kinds  of 
condensed  milk  which  are  widely  used — fresh  condensed 
milk  and  canned  condensed  milk.  Milk  is  first  heated 
up  to  near  boiling  point  and  a  large  portion  of  water  then 
removed  by  boiling  at  a  low  temperature  in  vacuum  pans. 
The  condensed  milk  is  then  filled  into  bottles  or  cans  if 
it  is  to  be  sold  in  its  fresh  state;  or  cane  sugar  is  added, 
and  it  is  then  filled  into  tin  cans  and  hermetically  sealed 
if  it  is  to  be  kept  for  any  length  of  time. 

During  the  past  three  or  four  years  there  has  been  a 
greatly  increased  sale  of  unsweetened  condensed  milk  put 
up  in  sealed  tin  cans.  These  milks  are  limpid,  yellow  in 
color,  and  have  a  strong  "  cooked  "  taste.  They  are  sold 
under  the  name  of  "  Evaporated  Creams,"  a  misleading 
term,  as  many  brands  of  condensed  milk  contain  more 
fat  than  these  so-called  creams.  The  labels  on  the  cans 
of  evaporated  cream  usually  state  that  it  is  simply  pure 
milk  thoroughly  sterilized  and  reduced  to  the  consistency 
of  cream.  These  evaporated  creams  are  apt  to  become 
putrid  when  diluted  and  exposed  to  the  air,  and  for  this 
reason  are  being  put  up  in  small  cans,  the  contents  of 
which  will  be  used  up  quickly. 


78  INFANT    FEEDING. 

There  has  recently  been  devised  a  process  of  condens- 
ing milk  without  the  aid  of  heat.  The  cream  is  first  re- 
moved by  a  separator  (43)  and  the  skim  milk  is  then 
frozen.  As  fast  as  crystals  of  ice  appear  the  milk  is 
stirred  and  in  time  becomes  like  slushy  snow.  The  wa- 
ter in  crystallizing  throws  out  the  proteids,  sugars,  and 
mineral  matter  of  the  milk  as  a  syrupy  mass.  The  frozen 
milk  is  then  put  in  a  centrifugal  machine,  such  as  is  used 
in  driving  out  the  molasses  from  raw  sugar,  and  the  syr- 
upy mass  of  proteids,  sugar,  and  mineral  matter  is  thus 
separated  from  the  ice  crystals.  The  cream  is  now  mixed 
with  the  syrupy  mass  and  the  mixture,  when  diluted  with 
three  parts  of  water,  equals  the  original  milk. 

As  yet  this  condensed  milk  is  not  on  the  market,  but 
if  it  becomes  possible  to  render  it  sterile  without  the  use 
of  heat,  so  that  it  can  be  kept  indefinitely,  it  is  likely  to 
become  a  very  useful  article  of  food. 

The  following  analyses  of  condensed  milks  furnished 
the  author  by  Major  Alvord,  Chief  of  Dairy  Division, 
United  States  Department  of  Agriculture,  are  of  milks 
bought  in  San  Francisco.  Only  four  States,  Illinois, 
New  York,  Ohio,  and  Oregon,  have  laws  (79)  relating  to 
the  quality  of  condensed  milk,  so  any  kind  of  condensed 
milk  can  be  sold  in  the  other  States.  These  analyses  do 
not  represent  all  the  brands  in  the  market  by  any  means, 
but  they  do  show  the  range  in  quality  likely  to  be  met 
with.  Any  of  the  evaporated  creams  or  unsweetened 
condensed  milks  may  be  tested  in  a  few  moments  by  the 
fat  and  specific  gravity  test  (75)  when  diluted  with  two 
parts  of  water,  quite  accurate  results  being  obtained. 
Sweetened  condensed  milks  cannot  be  easily  tested  in 


COW'S   MILK.  79 

this  way,  as  the  excess  of   sugar  interferes  with  the   fat 
test. 

Unsweetened  Condensed  Milk. 
Whole  Milk  (so-called  Evaporated  Creams). 


6S.27 
69.17 

69.  5  S 
72.78 
72.92 


Fat. 

Proteids. 

Milk 
sugar. 

Solids 
not  fat. 

Cane 

sugar. 

Ash. 

IO.IO 

7-36 

II.03 

r.85 

IO.4O 

8.OI 

20.43 



1.79 

9.02 

7-77 

10.62 

I.80 

9-37 

7.66 

17.85 

1. 61 

8-34 

6.00 

IS. 74 

I. 71 

Brand. 


Ideal. 

California  Poppy, 

Highland. 

Lily. 

Red  carnation. 


Evidently  Skimmed  or  Partly  Skimmed  Milk. 


74.29 

1.80 

8.97 

23.91 

2.39 

80.58 

5.70 

7.02 

13.72 

1.69 

Monarch. 
"99." 


Sweetened  Condensed  Milk. 

Whole  Milk. 


Water. 

Fat. 

Proteids. 

Milk 
sugar. 

Cane 

sugar. 

Ash. 

Brand. 

23.70 

25.25 
26.03 
27-52 
28.41 

IO.82 
ro.62 

8-54 
8.81 
S.44 

8.54 
7.90 

7.17 
7.4S 
7.23 

14.17 
12.53 
12.45 
12.77 
II.69 

39-85 
40.56 
41.82 
41.06 
4L52 

2.13 
I.84 
I.87 
I.63 
I.80 

Milk  Maid. 

Nestle's. 
Gold  Lines. 
Eagle  Falcon. 
Eagle. 

Evidently  Skimmed  or  Partly  Skimmed  Milk. 


25.68 

0.71 

10.35 

16.85 

43.09 

2.48 

Cowslip. 

25.88 

0.96 

10.64 

27.38 

34.07 

2.56 

Snake. 

28.48 

0.60 

7.90 

18.76 

41.77 

2.04 

Farm. 

29.67 

2.47 

10.45 

19.05 

36.00 

2.29 

Pearl. 

Condensed  Creams. 

Water. 

Fat. 

Proteids. 

Solids  not  fat. 

Ash. 

Brand. 

59.60 
65.26 
69.84 

34.19 

2S.26 

23.83 

6.21 

6.48 
6.33 

0.53 
O.56 
O.67 

Dahl's  Gold  Medal. 

Empress. 

California. 

CHAPTER    XI. 
BACTERIOLOGY   OF    MILK. 

47.  Practically  all  of  the  changes  that  take  place  in 
milk  that  is  kept  for  any  length  of  time  are  the  result  of 
bacterial  growth.  The  mere  presence  of  bacteria  in  milk, 
even  in  large  numbers,  however,  does  not  necessarily 
mean  that  the  milk  is  harmful  and  unfit  for  use  as  food. 
A  great  deal  of  misapprehension  exists  on  this  point,  and 
it  can  be  removed  only  by  a  better  knowledge  of  the  func- 
tion and  properties  of  bacteria.  To  many,  bacteria  sug- 
gest disease,  and  it  has  been  thought  that  all  bacteria 
should  be  destroyed;  but  now  it  is  known  that  their  in- 
discriminate destruction  would  prove  to  be  a  great  calam- 
ity, as  bacteria  are  absolutely  essential  to  the  life  of  plants 
and  animals,  the  function  of  most  bacteria  being  to  reduce 
to  gases,  and  soil,  which  is  a  mixture  of  earth  and  decom- 
posing organic  matter,  all  lifeless  organic  matter,  which 
then  serves  as  food  for  plants,  and  these  in  their  turn 
nourish  all  animal  life.  Bacteria  serve  other  useful  and 
valuable  purposes.  The  delicate  flavor  of  June  butter  is 
caused  by  bacterial  action,  and  the  manufacture  of  cheese 
is  largely,  if  not  wholly,  dependent  on  the  growth  of  bac- 
teria in  milk.  It  is  true  that  disease  is  caused  by  some 
kinds  of  bacteria,  but  all  bacteria  should  not  be  con- 
demned and  destroyed,  even  if  this  could  be  done,  be- 
cause a  few  species  cause  disease. 


BACTERIOLOGY   OF   MILK. 


81 


o° 


Fig.  ii. — Showing   Budding 
of  Yeast.     (Conn.) 


0U8 


As  bacteria  are  everywhere  present  and  are  sure  to  be 
found  in  milk,  a  knowledge  of  their  nature  and  of  the 
conditions  under  which  they  gain  ac- 
(^V    f~^\  Jl       cess  to  the  milk  and  cause  it  to  change 
^^"^  ?     u  y       or  become  harmful  is  essential. 
^J  S*\  48.  Bacteria. —  Bacteria  are  micro- 

scopic, unicellular,  colorless  plants,  be- 
longing to  the  class  called  fungi.  They 
are  closely  related  to  ^ 

the    yeasts,   but    are      yj     Q_J 
smaller  and  also  differ  from  the  yeasts  in      r\ 
their  methods  of  reproduction.     Yeasts 
multiply  by  budding,  while  bacteria  mul-     F,G  f12T:-Showi"£  Fis; 

x     J        J  "  sion of  Bacteria.  (Conn.) 

tiply  by  two  different  methods :     1st.  By 
fission,  in  which  the  cell  divides  through  the  centre,  pro- 
ducing another  full-fledged  bacterium.     2d.  By  specula- 
tion, in  which  spores  are  formed  in  the  interior  of  the  cell, 
which  breaks  up  and  sets  them  free.     These  spores  when 

placed     in     favorable 


surroundings  germi- 
nate and  become  ac- 
tive bacteria. 

Not  all  species  of 
bacteria     are     spore- 
bearing,  and  this  fact 
has  great  importance 
in  the  preservation  of 
milk  and  food ;  for  while  active  bacteria  are  almost  with- 
out exception   easily  destroyed  by  a  moderate  degree  of 
heat,  spores  in  water  or  milk  are  not  destroyed  by  boiling. 

They  may  be  dried  and  kept  for  months  or  years,  and  then 
6 


Fig.  13. — Showing  Formation  of  Spores.     (Conn.) 


82 


INFANT   FEEDING. 


when  placed  under  favorable  conditions  will  germinate 
and  develop  into  active  bacteria.  Many  of  the  harmful 
changes  in  milk  are  caused  by  spore-bearing  bacteria. 


#° 


Fig.  14. — a,  Spheres;  6,  rods;  c,  spirals.     (Conn.) 

Classification  of  Bacteria. — Bacteria  are  divided  ac- 
cording to  their  form  into  three  groups: 

1.  Spherical  bacteria — coccus. 

2.  Rod-shaped  bacteria — bacillus  and  bacterium. 

3.  Spiral  bacteria — spirillum. 


Fig.  15  — a,  Streptococcus;  £•,  micrococcus  :  c,  sarcina.     (Conn.) 

Spherical  bacteria  are  further  classified  according  to 
the  way  in  which  they  group  themselves  .during  the  proc- 


BACTERIOLOGY   OF   MILK.  83 

ess  of  division,  as  streptococcus,  in  chains;  micrococcus, 
in  irregular  masses,  and  sarcina,  solid  masses  in  groups 
of  four. 

49.  Bacteria  that  grow  best  in  the  presence  of  oxygen 
or  air  are  called  aerobes ;  those  that  grow  best  in  the  absence 
of  oxygen  or  air  are  called  anaerobes.  Bacteria  which 
will  grow  only  under  one  of  these  conditions  are  called 
obligate  aerobes  or  anaerobes,  while  those  s'pecies  that  will 
grow  either  in  the  presence  or  absence  of  oxygen  are 
called  facultative  aerobes  or  anaerobes.  The  greater 
number  of  species  of  bacteria  attack  and  live  upon  lifeless 
organic  matter  and  are  called  saprophytes ;  those  species 
that  attack  living  matter  are  called  parasites. 

50.  Rate  of  Growth  of  Bacteria. — Bacteria  increase  in 
numbers  at  a  prodigious  rate.  If  nothing  interfered,  in 
twenty-four  hours  a  single  bacterium  would  produce  about 
seventeen  million  others.  This  rate  of  increase  is  not 
met  with  in  practice ;  but,  according  to  Conn,  a  specimen 
of  milk  containing  153,000  bacteria  to  the  cubic  inch  con- 
tained twenty-four  hours  later  85,000,000,  and  a  sample  of 
fresh  cream,  containing  44,000  bacteria  to  the  cubic  centi- 
metre, contained  1,300,000,000  when  sour  enough  to  churn. 
The  rapidity  of  increase  depends  largely  on  the  tempera- 
ture. Below  450  F.  there  is  comparatively  little  growth 
of  bacteria;  but  as  the  temperature  approaches  ioo°  F., 
the  rate  of  growth  increases  rapidly. 

5'i.  Food  of  Bacteria. — Most  bacteria  must  have  a  food 
supply  of  nitrogenous  matter  (proteid),  carbohydrates 
(sugar,  starch,  or  cellulose),  mineral  matter,  and  water. 
Furthermore,  their  food  must  be  in  a  soluble  form  so  that 
it  can  pass  through  the  cell  wall  of  the  bacteria  and  be 


84  INFANT    FEEDING. 

not  too  concentrated.  Bacteria  cannot  grow  in  substances 
as  thick  as  syrup.  Bacteria  that  can  attack  insoluble 
matter  secrete  enzymes  that  digest  or  convert  the  insolu- 
ble food  material  into  assimilable  forms.  Thus  in  milk 
some  species  of  bacteria  will  secrete  rennet  that  will  curdle 
the  casein  of  milk,  and  trypsin  that  will  dissolve  or  pep- 
tonize it.  Other  bacteria  also  secrete  enzymes  that  will 
digest  or  decompose  starch,  sugar,  cellulose,  fat,  urea,  and 
other  substances. 

52.  Souring  of  Milk. — As  ever}7  one  knows,  the  most 
common  change  in  milk  is  souring.  Milk  sours  because 
several  species  of  bacteria  attack  the  sugar  of  the  milk 
and  convert  it  into  lactic  acid,  which  throws  the  casein  out 
of  solution  (37).  These  bacteria  may  be  classed  as  harm- 
less bacteria,  for  sour  milk  is  a  wholesome  article  of  food 
and  is  used  in  cooking.  Before  baking  powder  became 
so  common,  sour  milk  was  used  with  baking  soda  to  make 
cake  and  biscuit  rise. 

It  is  popularly  believed  that  thunder  causes  milk  to 
sour,  but  it  has  been  found  that  the  thunder  or  electricity 
of  the  air  has  nothing  to  do  with  the  souring  of  the  milk, 
but  that  the  atmospheric  conditions  during  a  thunder 
storm  are  favorable  to  the  growth  of  lactic-acid  bac- 
teria. 

Fresh  milk  always  contains  several  species  of  bacteria, 
and  if  the  milk  is  warm  enough  they  commence  to  grow 
at  once.  The  conditions  in  the  milk  are  generally  most 
favorable  for  the  growth  of  the  species  that  attack  the 
sugar  and  produce  lactic  acid ;  and  if  there  are  any  of 
these  bacteria  present,  as  is  generally  but  not  always  the 
case,  they  soon  outstrip  the  other  species  and  kill  them 


BACTERIOLOGY   OF   MILK.  85 

off;  hence  after  a  few  hours  an  examination  of  the  milk 
will  often  show  ninety-nine  per  cent  of  the  bacteria  in  the 
milk  to  be  of  the  souring  variety.  When  bacteria  that 
cause  souring  are  not  present,  the  other  species  which 
attack  the  fat  and  proteids  of  the  milk  grow  and  produce 
rancidity  of  fat  and  many  changes  in  the  proteids. 

53.  Peptonizing  Bacteria  in  Milk. — When  the  proteids 
of  milk  are  attacked  by  bacteria,  they  may  be  first  curdled 
by  rennet  and  then  peptonized  by  trypsin,  both  secreted 
by  bacteria,  or  the  proteids  may  be  peptonized  without 
first  being  curdled.  Such  milk  does  not  sour,  but  acquires 
a  bitter  taste.  Bacteria  that  produce  these  changes  are 
normally  present  in  milk,  but  are  usually  held  in  check 
by  the  souring  species;  sometimes,  however,  poisonous 
products  are  produced  by  bacterial  action  on  proteids  of 
milk. 

54-  Decomposition  of  Proteids. — The  decomposition  of 
proteid  matter  is  brought  about  chiefly  by  the  action  of 
decomposition  bacteria.  When  the  process  of  decomposi- 
tion is  caused  by  aerobic  bacteria  in  the  presence  of  an 
abundance  of  air,  it  is  called  decay  and  the  proteid  matter 
is  reduced  to  simple  harmless  forms;  but,  when  the  de- 
composition is  caused  by  facultative  aerobic  or  anaerobic 
bacteria  in  the  absence  of  an  abundance  of  air,  the  process 
is  called  putrefaction.  Here  the  proteid  matter  is  not 
completely  reduced  to  simple  harmless  forms ;  foul-smell- 
ing gases  are  evolved  and  oftentimes  substances  that  are 
intensely  poisonous  are  also  produced.  These  poisons 
may  be  secretions  or  excretions  of  the  putrefactive  bac- 
teria, or  partially  reduced  proteid  matter.  Under  the  ac- 
tion of  aerobic  bacteria,  in  the  presence  of  plenty  of  air, 


86 


INFANT   FEEDING. 


these  gases  and  poisons  are  destroyed.  The  process  in- 
volved in  the  decay  or  putrefaction  of  proteid  matter  is 
not  understood.  Putrefactive  bacteria  are  present  every- 
where, but  particularly  in  rich  soil  and  in 
manure.  A  gram  of  rich  soil  may  contain 
100,000,000,  and  a  gram  of  fresh  cow's 
manure  as  many  as  375,000,000  bacteria, 
most  of  which  will  cause  decomposition 
in  proteid  matter.  This  fact  suggests  the 
importance  of  keeping  cows  and  stables 
clean. 

Other  Bacterial  Changes  in  Milk. — 
Slimy  milk  is  caused  by  bacteria  found  in 
water,  and  "  gassy  "  milk  by  bacteria  found 
particularly  in  manure  particles.  Soapy, 
blue,  red,  and  yellow  milks  are  also  the 
result  of  bacterial  action,  but  are  not 
common  (see  Fig.  7$- 

The  bacterial  changes  of  milk  may  be 

summed  up  as 
souring,  pep- 
tonizing, pu- 
trefactive, and 

the  development  of  odors,  bit- 
ter taste,  sliminess,  soapiness, 
colors,  and  gases. 

Bacterial  Diseases    Trans- 
mitted    by    Milk.  —  Typhoid 
fever  is  easily  transmitted  by 
infected  milk.     Outbreaks  of  diphtheria  and  scarlet  fever 
have  been  traced  to  milk  supplies,  and  tuberculosis  may 


16.— Slimy  Milk. 
(Russell.) 


Fig.  17.  — Udder  and  Teat.     (Russell.) 


BACTERIOLOGY   OF   MILK. 


87 


possibly  but  not  necessarily  be  caused  by  milk  containing 
tubercle  bacilli  (see  Chapter  XV.). 


i°s? 


How  Bacteria  Get  into  Milk  and  Increase  in 
Numbers. 

55-  From  the  Cow's  Udder. — Just  inside  the  cow's  teat 
is  a  small  cavity  that  always  contains  a  small  quantity  of 
milk.  During  the  intervals  between  milkings  bacteria  from 
the  air  lodge  on  the  moist  teat  and  make  their  way  into 
this  cavity  where  they  grow.  To  quote  Russell :  "  As  a  rule 
the  number  of  different  species  found  in  the  fore  milk  is 
usually  small,  not  more  than  one  or  two  forms  being  pres- 
ent at  any  time.  As 
to  the  character  of 
these  forms  data  are 
conflicting.  Har- 
rison reports  finding 
peptonizing  bacteria 
in  some,  and  Mar- 
shall states  that  or- 
ganisms are  found 
that  resist  pasteuriz- 
ing. .  .  .  Bolley  in 
thirty  experiments 
found  twelve  out  of  sixteen  species  to  belong  to  the 
lactic-acid  class.  ...  If  the  fore  milk  is  received  into  a 
separate  vessel  and  kept  protected  from  the  air,  it  will  be 
generally  noted  that  it  sours  more  rapidly  than  the  re- 
mainder of  the  milk."  In  the  report  of  a.  series  of 
bacterial  examinations  of  milk,  D.  H.  Bergy  (Penn.  Dept. 
Agr.  Rept.,  1900)  states:  "Milk  taken  directly  from  the 


Fig.  18. — Bacteria  from  Cream.     (Conn.)     c  and  d  produce 
good  butter. 


88  INFANT   FEEDING. 

udder  in  the  ordinary  way  and  collected  in  sterile  test 
tubes  was  always  found  to  contain  bacteria  of  the  group 
streptococci.  The  number  in  the  first  milk  drawn  was 
usually  greater  than  [in]  the  latter  portion."  Strepto- 
cocci are  usually  looked  upon  by  physicians  as  dangerous 
bacteria,  but  it  has  been  found  that  good  butter  flavor  is 
produced  by  some  species  of  streptococci  (Fig.  18). 


Fig.  iq. — Tuberculous  Udder.     (Russell.) 


If  the  first  few  jets  from  each  teat  are  thrown  away,  the 
remaining  portion  of  the  milking  will  be  quite  free  from 
bacteria,  provided  the  cow  has  no  disease  of  the  udder. 
No  milk  from  a  diseased  udder  should  be  used  as  food. 
Tuberculous  udders  always  secrete  milk  containing  tu- 
bercle bacilli,  and  although  there  is  some  doubt  about 
bovine  tuberculosis  infecting  human  beings  through  milk, 
no  risk  should  be  taken.     When  a  cow's  udder  is  tuber- 


BACTERIOLOGY   OF    MILK.  89 

culous,  it  is  time  to  stop  the  use  of  her  milk,  whatever 
may  be  said  of  the  safety  of  the  milk  from  cows  that 
simply  react  to  the  tuberculin  test.* 

56.  From  the  Cow's  Body. — If  the  cow's  body  is  not 
kept  clean,  more  or  less  dirt  is  bound  to  be  loosened  and 
to  fall  into  the  milk  pail,  along  with  some  hairs,  during  the 
process  of  milking.  On  a  single  cow's  hair  several  hun- 
dred bacteria  have  been  counted,  and,  as  previously  stated, 
soil  and  cow's  manure,  which  is  the  dirt  usually  found  on 
the  cow's  body,  contains  millions  of  bacteria  per  gram  (54). 
If  the  cow  has  been  wading  in  slimy,  stagnant  water,  the 
scum  from  this  water  dries  on  the  cow's  body  and  some 
of  it  will  get  into  the  milk;  this  dried  scum  is  particularly 
injurious  to  milk.  The  bacteria  that  get  into  milk  with 
filth  are,  as  a  class,  the  ones  that  cause  the  most  damage 
to  milk  as  a  food,  for  many  of  these  species  decompose  or 
putrefy  the  proteids  of  the  milk.  They  can  be  kept  out 
of  the  milk  by  keeping  the  cows  clean. 

Example  f :  Milk  from  four  dirty  cows  in  a  clean  barn 
with  clean  milkers  gave  an  average  of  ninety  thousand 
bacteria  to  the  cubic  centimetre.  Milk  from  four  other 
cows  of  the  same  herd,  carefully  cleaned  and  milked  by 
the  same  man,  gave  an  average  of  only  two  thousand. 

57-  From  Dust.  —  Stable  dust  contains  enormous 
numbers  of  bacteria,  and  if  the  cows  are  eating  dry 
hay,  or  if  the  milker's  clothes  are  dusty,  the  milk  will 

*This  test  consists  of  injecting  into  an  animal  certain  products  de- 
rived from  tubercle  bacilli.  If  the  animal  is  tuberculous  they  cause  a  rise 
of  temperature. 

f  Report  of  the  summer  work  of  the  Milk  Commission  of  the  Medical 
Society  of  the  County  of  New  York.  (Bacterial  examinations  made  by 
Dr.  Sarah  Belcher.) 


9o  INFANT   FEEDING. 

receive  a  great  many  bacteria  with  the  dust  that  is  sure 
to  settle  into  the  milk  pail.  Dust  can  be  kept  out  of  milk 
by  wiping  the  cow  with  a  damp  cloth  and  by  sprinkling 
the  stable. 

Example  * :  Milk  from  each  of  twelve  cows  in  a  stable 
showed  low  bacterial  count  except  from  one  which  stood 
next  to  a  pile  of  dry  feed ;  her  milk  contained  one  mil- 
lion bacteria  to  the  cubic  centimetre. 

58.  From  the  Milker. — If  the  milker's  hands  are  chap- 
ped or  not  clean,  or  if  he  is  diseased,  or  is  nursing  a  person 


Fig.  20. — A,  a,  Improper  joints  in  dairy  utensils.     B,  Proper  joints  closed  with  solder. 
(After  Russell.) 

suffering  from  some  infectious  disease,  the  milk  is  more 
than  likely  to  be  infected  by  him.  It  is  in  this  way  that 
typhoid  fever,  scarlet  fever,  diphtheria,  and  infectious  dis- 
ease germs  find  their  way  into  milk.  Milkers  should  wear 
white  duck  suits  or  blue  overalls  that  are  kept  clean  by 
frequent  washing. 

59-  From  Dairy  Utensils. — Any  part  of  a  milk  pail, 
vat,  cooler,  can,  bottle,  or  bottle  filler  that  cannot  be  kept 
perfectly  clean,  always  contains  many  bacteria  that  will 
infect  any  milk  they  may  come  in  contact  with,  and  for 

*  See  last  note  on  page  Sg. 


BACTERIOLOGY   OF   MILK.  91 

this  reason  all  dairy  utensils  should  have  perfectly  tight 
smooth  seams  and  joints;  even  then  it  is  almost  impos- 
sible to  keep  the  best-made  utensils  free  from  bacteria. 
Washing  utensils  with  ordinary  well  water  or  brook 
water  may  infect  the  milk  with  typhoid  germs;  they 
should  be  washed  with  boiling  water  and  steamed  if 
possible. 

Example*:  With  ordinary  milk  pail  and  strainer  the 
bacterial  count  was  eighty  thousand;  with  sterilized  pail 
and  strainer  the  same  day,  in  the  same  barn,  and  with 
the  same  cows  five  thousand  bacteria  to  the  cubic  centi- 
metre were  counted. 

60.  By  Growth. — When  the  milk  leaves  the  cow  it  is  at 
a  temperature  of  nearly  ioo°  F.,  which  is  the  ideal  tempera- 
ture for  rapid  growth  of  bacteria.     If  the  milk  is  allowed 


progeny  or  A     /><r0  ° 

SINGLE  GERM       et^jNJ 

N  TWELVE  HOURS  Wr^^K 


Fig.  21. — Showing  the  Effect  of  Cooling  Milk  on  the  Growth  of  Bacteria.     (Russell.) 

to  stand,  the  bacteria  grow  rapidly,  and  in  a.  short  time 
each  bacterium  will  produce  hundreds  of  others.  This 
increase  in  numbers  by  growth  may  easily  be  prevented 
by:  (1)  promptly  cooling  the  milk  to  below  45°  F.,  and 
keeping  it  cool ;  (2)  by  heating  the  milk  to  destroy  the 

*  See  last  note  on  page  S9. 


92 


INFANT   FEEDING. 


bacteria;  or  (3)  by  the  addition  of  chemical  preservatives. 
The  following  figures  of  Cnopf  and  Escherich,  quoted  by 
Russell,  are  highly  instructive,  as  is  also  the  illustration 
by  Russell. 


Rate  of  Growth  of  Single  Germ. 


Two  hours. 

Three  hours. 

Four  hours. 

Five  hours. 

Six  hours. 

54CF 

o7;  F 

4 
23 

6 
60 

8 
215 

26 
1,830 

435 
3,800 

Bacterial  Count  of  Milk. — From  the  foregoing  it  will 
be  seen  that  bacteria  originally  get  into  milk  principally 
through  lack  of  cleanliness  about  the  dairy,. also  that  no 
matter  how  few  bacteria  were  present  in  the  milk  originally, 
it  will  soon  contain  enormous  numbers  if  allowed  to  stand 
for  any  length  of  time  at  anywhere  near  body  tempera- 
ture. Therefore,  counting  the  numbers  of  bacteria  in 
natural  milk — that  is,  milk  that  has  not  been  heated  to 
kill  the  bacteria  or  to  which  chemical  preservatives  have 
been  added — is  a  valuable  way  of  telling  under  what  con- 
ditions it  has  been  produced  and  kept.  Milk  produced  in 
dirty  surroundings  will  always  contain  large  numbers  of 
bacteria,  while  milk  produced  where  cleanliness  is  the  rule 
will  contain  few  bacteria.  If  the  milk  is  properly  cooled 
and  kept  cool  there  will  be  but  a  slight  increase  in  the 
numbers  of  the  bacteria  in  the  milk  after  milking.  There- 
fore it  is  safe  to  say  that  natural  milk  containing  few  bac- 
teria came  from  a  clean  dairy  and  that  the  milk  was  kept 
cool ;  and  that  natural  milk  containing  large  numbers  of 
bacteria  came  from  a  dirty  dairy,  or  was  not  kept  cool  if 
from  a  clean  dairy,  or  that  the  dairy  was  dirty  and  the 
milk  was  also  not  cooled.  Low  bacterial  count  in  natural 
milk  means  that  the  milk  has  been  produced  under  clean 


BACTERIOLOGY   OF   MILK.  93 

conditions,  and  that  little  or  no  change  has  taken  place 
in  it. 

As  all  milk  contains  a  certain  number  of  bacteria, 
what  is  to  be  desired  is  a  knowledge  of  what  species  of 
bacteria  cause  sickness  and  where  they  come  from.  Such 
information  can  be  obtained  only  by  much  patient  work 
on  milk  that  has  actually  caused  sickness. 

In  the  section  on  testing  milk  (p.  140)  will  be  found  a 
chapter  by  Prof.  H.  W.  Conn,  on  the  bacteriological  ex- 
amination of  milk.  The  great  experience  of  Professor 
Conn  and  his  many  bacterial  discoveries  regarding  milk 
make  his  methods  of  work  of  great  value,  and  suggestive 
to  workers  not  familiar  with  bacterial  studies  in  milk. 


CHAPTER    XII. 
PRESERVATION   OF    MILK. 

In  the  preceding  chapter  (60)  it  was  shown  that  the 
bacterial  development  and  changes  in  milk  could  be  pre- 
vented (1)  by  heating  to  kill  the  bacteria;  (2)  by  the  addi- 
tion of  certain  chemicals;  and  (3)  by  keeping  the  milk  at 
temperatures  below  45 °  F.,  when  bacteria  do  not  grow  to 
any  extent.  On  these  three  principles  all  methods  of 
milk  preservation  are  based. 

61.  Sterilization  and  Pasteurization.  —  Before  the 
cause  of  the  changes  that  take  place  in  milk  was  discov- 
ered, it  was  known  that  scalding  or  boiling  would  prevent 
it  from  souring.  With  a  knowledge  of  bacteria  and  their 
supposed  always  dangerous  properties,  came  the  belief 
that  all  milk  for  infants  and  possibly  for  adults  should  be 
sterilized — heated  to  2120  F.,  so  as  to  kill  all  bacteria  pres- 
ent. Such  milk  had  a  "cooked"  taste,  and  its  physical 
and  chemical  properties  were  changed  (42),  and  few 
adults  would  use  it.  It  was  then  discovered  that  at  tem- 
peratures ranging  from  1400  to  1750  F,,  most  of  the  bacte- 
ria found  in  milk  were  destroyed  if  the  milk  was  properly 
handled  during  heating.  This  process  is  called  pasteu- 
rization after  Pasteur,  who  first  used  it  to  any  extent. 
Russell  states  that  in  some  milk  pasteurized  on  a  com- 
mercial scale  at  the  Wisconsin  Dairy  School,  there  were 
less  than  one  thousand  bacteria  per  cubic  centimetre  in 


PRESERVATION    OF   MILK.  95 

half  of  the  samples,  while  the  average  of  twenty-five 
samples  was  6,140  per  cubic  centimetre.  Even  at  these 
low  temperatures  the  taste  of  the  milk  is  slightly  changed 
and  the  natural  arrangement  of  the  fat  emulsion  is  de- 
stroyed (42). 

62.  In  some  cities  milk  dealers  pasteurize  their  milk 
before  delivering  it  to  their  customers,  but  such  milk  may 
in  the  end  prove  more  injurious  than  natural  milk.  If 
the  milk  was  originally  dirty  or  contained  as  much  as  .2 
per  cent  acid  produced  by  the  growth  of  bacteria,  it  will 
not  pasteurize  satisfactorily,  as  many  spore-bearing  bacte- 
ria will  be  present.  The  heat  destroys  the  active  bacteria, 
most  of  which  produce  souring,  but  spores  are  not  de- 
stroyed (48). 

Pasteurized  milk  will  seldom  sour,  but  unless  the  milk 
is  cooled  the  spores  will  germinate  and  produce  bacteria 
that  will  attack  the  proteids  of  the  milk,  and  it  is  the 
products  of  some  of  these  bacteria  that  are  thought  to  be 
poisonous.  These  spores  cannot  grow  in  sweetened  con- 
densed milk  (46),  because  it  is  too  concentrated  (51). 

A  very  convincing  demonstration  of  the  presence  and 
effect  of  spores  in  milk  is  as  follows : 

Take  four  test-tubes  of  fresh  milk ;  to  one  add  a  little 
dried  cow's  manure ;  to  another  a  little  dust  from  a  city 
street.  Boil  both  of  these  and  also  a  tube  of  the  natural 
milk.  Plug  all  four  with  cotton  and  set  them  in  a  cup  of 
tepid  water.  The  unboiled  milk  will  probably  sour  in  a 
few  hours.  The  plain  boiled  milk  may  not  change  for 
days,  while  that  with  the  cow's  manure  or  dust  will  proba- 
bly curdle  without  the  production  of  acid  in  ten  or  twelve 
hours,  owing  to  the  development  of  spores  into  bacteria 


96  INFANT   FEEDING. 

that  attack  the  proteids  of  the  milk.  For  this  reason 
boiled  milk  sometimes  gives  off  an  extremely  offensive 
odor  if  kept  for  any  length  of  time.  If  milk  is  to  be  made 
absolutely  sterile  it  must  be  heated  several  times,  with  in- 
tervals between,  to  allow  the  spores  to  germinate  so  that 
they  can  be  killed  by  subsequent  Heatings. 

It  will  be  seen  that  neither  pasteurization  nor  ordinary 
sterilization  will  enable  milk  to  be  kept  for  any  great 
length  of  time  without  cooling,  so  these  processes  simply 
allow  of  a  little  more  carelessness  in  the  handling  of  milk 
during  and  after  milking,  and  put  off  for  a  few  hours  the 
changing  of  the  milk.  In  Europe  pasteurization  is 
commonly  used,  for  reasons  explained  in  another 
place  (65). 

Home  pasteurization  of  milk  is  often  of  great  value,  as 
the  milk  is  usually  consumed  before  the  spores  have  time 
to  germinate  and  affect  the  milk  (14°). 

63.  Chemical  Preservatives.  —  Many  chemical  sub- 
stances have  the  power  of  preventing  the  growth  of  bac- 
teria, and  are  often  put  in  the  milk  by  milkmen  to  prevent 
its  souring.  While  contrary  to  law  in  most  States,  the  use 
of  these  preservatives  is  not  uncommon,  as  they  save  the 
expense  of  keeping  the  milk  clean  in  the  first  place,  the 
cost  of  pasteurizing  and  of  the  ice  necessary  to  keep  the 
milk  cool,  and  besides  the  milk  appears  to  families  to  be  of 
exceptionally  good  keeping  quality. 

The  following  analyses  and  comments  taken  from  the 
Year  Book  of  the  Department  of  Agriculture  for  1900  will 
prove  instructive  in  connection  with  chemical  milk  and 
food  preservatives. 

Dry  Antiseptic. — Boric  acid,  77.2  per  cent;  dry  borax 


PRESERVATION   OF   MILK.  97 

equivalent  to  42.98  per  cent  of  crystallized  borax.  Direc- 
tions: One  ounce  to  ten  pounds  sausage  or  to  four  gal- 
lons milk. 

Iceline. — A  1 .92-per-cent  solution  of  formaldehyde. 
Second  analysis;  A  3.66-per-cent  solution  formaldehyde. 
Directions:  A  tablespoonful  to  ten  gallons  of  milk;  one 
and  one-half  to  two  times  as  much  to  cream  and  butter- 
milk. A  tablespoonful  to  each  gallon  of  cream  intended 
for  cream  puffs. 

Freezine. — Liquid  containing  5.19  per  cent  formalde- 
hyde. Second  analysis:  Liquid  containing  2.52  per  cent 
formaldehyde.  Directions:  One  tablespoonful  to  ten  gal- 
lons of  milk,  six  and  two-thirds  gallons  of  cream  or  butter- 
milk, or  three  and  one-half  gallons  of  ice  cream;  one 
tablespoonful  to  each  gallon  of  cream  intended  for  cream 
puffs. 

Preserving  Salts. — Six  samples,  Nos.  1  to  6  inclusive, 
are  offered  for  different  classes  of  foods  and  sold  at  differ- 
ent prices,  but  are  identical  in  composition.  They  con- 
tain about  30  per  cent  of  borax  and  10  per  cent  of  salt. 
Directions:  From  three  to  four  ounces  to  one  hundred 
pounds  of  food. 

" A"  Preservative. — Percentage  composition:  Borax, 
68;  salt,  32.  Second  analysis:  Borax,  75 ;  salt,  19.  Di- 
rections :  Mix  one-half  pound  with  one  hundred  and  fifty 
pounds  of  chopped  meat ;  dust  one  pound  over  five  hun- 
dred pounds  of  fresh  meat ;  immerse  poultry,  drawn  or 
undrawn,  in  a  solution  of  one-quarter  pound  in  two  gal- 
lons of  water  for  ten  minutes. 

Cream  Albuminoid. — 50.4  per  cent  boric  acid,  mixed 
with  some  proteid  body,  apparently  gelatin  (see  45). 


98  INFANT   FEEDING. 

No  Ice  Needed  "  3f"  Preservaline. — A  four-per-cent 
solution  of  formaldehyde. 

Special"  M"  Preservaline. — Solution  containing  1.99 
per  cent  formaldehyde. 

Patent  "  M"  Preservaline. — The  sample  contained 
83  per  cent  of  boric  acid  and  17  per  cent  of  borax. 

Milk  Sweet. — A  3.90-per-cent  solution  of  formaldehyde. 
A  10-per-cent  solution  of  formaldehyde. 

Ozone  Antiseptic  Compound. — The  sample  contained 
51  per  cent  of  boric  acid  and  72  percent  of  borax,  the 
high  total  (123)  being  due  to  partial  dehydration.  Direc- 
tions: A  tablespoonful  to  twenty  or  thirty  quarts  of  milk 
or  ten  pounds  of  butter  or  cheese. 

" Preservative '." — Sodium  sulphite,  65  per  cent;  so- 
dium sulphate,  34  per  cent;  colored  with  an  aniline  dye. 
Directions :  One  ounce  to  fifty  pounds  of  chopped  meat. 

"  It  will  be  noticed  that  some  preservatives  have  been 
examined  by  different  analysts  with  widely  varying  results, 
indicating  that  the  composition  of  some  commercial  prep- 
arations is  not  constant.  One  preservative  was  found  to 
consist  largely  of  salicylic  acid  in  1897  and  of  benzoic  acid 
in  1900. 

"  The  wide-spread  use  of  these  preparations  is  sug- 
gested by  a  case  recently  reported,  where  a  preserving  fluid 
had  been  added  to  milk  first  by  the  farmer,  then  by  the 
collector  to  whom  he  sold,  again  by  the  wholesale  dealer 
in  the  city,  and  finally  by  the  retail  dealer  who  delivered 
it  to  the  consumer.  The  facts  were  developed  by  an 
investigation  occasioned  by  the  illness  of  children  who 
drank  the  '  doctored  '  milk." 

According  to   Bigelow :    "  A  pound  of  meat  treated 


PRESERVATION    OF    MILK.  99 

according  to  directions  with  a  boric-acid  preservative  will 
contain  from  five  to  nineteen  grains,  while  an  infant  who 
is  fed  each  day  a  quart  of  milk  so  treated  will  receive 
eight  grains,  or  a  fair-sized  dose  for  an  adult."  He  also 
states  that  the  use  of  formaldehyde  "  as  a  food  preserva- 
tive dates  back  to  about  1895."  •  •  •  "  Not  only  does  it  in- 
terfere with  digestion  to  a  marked  extent,  but  it  has  been 
definitely  proved  that  a  compound  is  formed  with  the 
casein  of  milk  which  causes  the  latter,  when  treated  with 
dilute  acid  such  as  exists  in  the  gastric  juice,  to  separate 
in  hard  lumps  that  are  attacked  only  with  difficulty  by 
digestive  ferments.  The  addition  of  formaldehyde  to  milk 
has  become  only  too  common,  and,  considering  the  fact 
that  other  and  less  objectionable  preservatives  will  accom- 
plish the  same  object,  its  use  should  be  condemned  in 
unqualified  terms."  Formaldehyde  is  the  basis  of  many 
embalming  fluids. 

64.  Filtration  and  Clarification  of  Milk. — Attempts 
have  been  made  by  enterprising  milk  dealers  to  improve 
their  milk  by  filtering  to  remove  dirt.  The  appearance  of 
the  milk  is  improved,  as  no  sediment  deposits  if  the  milk 
stands  for  some  time,  but  little  or  no  effect  is  had  in  re- 
ducing the  bacterial  count. 

Clarified  milk  was  advocated  for  a  time,  it  being 
cleaned  or  clarified  by  being  passed  through  a  separator 
which  threw  the  foreign  matter  out  as  "  separator  slime  " 
(44).  This  improves  the  milk  in  cleanliness,  but  breaks 
up  the  natural  emulsion  of  the  fat  (42),  interferes  with 
cream  rising,  and  changes  the  physical  character  of  the 
milk.  Babcock,  after  three  years'  experimenting  with  this 
process,  stated:  "Although  cleaning  milk  with  a  separa- 


100 


INFANT   FEEDING. 


tor  has  not  accomplished  all  that  we  had  hoped  in  the 
treatment  of  milk  for  cheese,  we  feel  that  it  has  been  of 
great  benefit,  as  it  has  in  nearly  every  case  improved  the 
quality  of  the  cheese,  and  the  improvement  has  been 
more  marked  with  tainted  milks  than  with  those  in  good 
condition." 


Fig.  22—  Milk  Filter. 


Filtered  and  clarified  milks  must  be  kept  cool,  or  they 
will  spoil  as  Avell  as  uncleaned  milk. 

65.  Cleanliness  and  Low  Temperahires. — If  no  bacte- 
ria found  their  way  into  milk  it  would  remain  unchanged 
indefinitely,  except  for  the  action  of  the  enzymes  natural 
to  all  milks  (32  B).  But  no  matter  how  much  care  is  ex- 
ercised, some  bacteria  will  get  into  milk.     If  the  tempera- 


PRESERVATION    OF   MILK.  101 

ture  is  kept  below  45  °  F.,  they  will  not  grow  and  affect 
the  milk,  and  by  the  free  use  of  ice  it  is  possible  to  keep 
clean  milk  for  several  weeks  in  good  condition.  Without 
the  use  of  ice  even  pasteurized  milk  will  soon  change. 
By  care  in  producing  milk  the  number  of  bacteria  can  be 
kept  as  low  as  that  of  commercial  pasteurized  milk  (61). 
Thus,  as  far  as  keeping  qualities  go,  this  natural  milk  is 
as  good  as  the  pasteurized  milk  and  much  better  in  that 
no  changes  have  been  produced  by  heating.  Milk  con- 
taining large  numbers  of  ordinary  dairy  bacteria  will  keep 
better  and  be  better  if  ice  is  used,  than  if  pasteurized  and 
no  ice  is  used  to  keep  it  cool  afterward ;  but  will  spoil 
sooner  than  pasteurized  milk  if  neither  is  iced. 

In  Europe,  pasteurization  is  conducted  by  milk  com- 
panies on  a  large  scale,  as  ice  is  not  used  as  in  America. 
According  to  figures  obtained  through  the  United  States 
Department  of  State,  the  estimated  annual  consumption 
of  ice  in  England  is  450,000  tons  (long)  and  in  London 
160,000  tons,  while  Paris  consumes  about  65,000  tons. 
New  York  is  thought  to  use  3,000,000  tons,  and  Chicago 
2,000,000  tons  of  ice  annually.  The  London  Daily  Mail, 
June  21,  1900,  speaking  of  ice  in  London,  says:  "The 
demand  is  rapidly  increasing  now  that  the  public  have 
awakened  to  an  intelligent  appreciation  of  the  cheapness 
and  usefulness  of  the  commodity." 

66.  At  the  Paris  Exposition  of  1900  there  was  an  ex- 
hibit of  American  dairy  products  in  charge  of  Maj.  H. 
E.  Alvord,  chief  of  the  Dairy  Division  of  the  United 
States  Department  of  Agriculture.  Among  the  articles 
exhibited  was  fresh  milk  and  cream  in  bottles  shipped 
regularly  every  two  or  three  weeks  from  farms  in  Illinois, 


102  INFANT   FEEDING. 

New  Jersey,  and  New  York.     To  quote  Major  Alvord's 
report : 

"  Foreign  visitors  and  expert  milk  dealers  on  the  jury 
were  hard  to  convince  that  nothing  but  'cleanliness  and 
cold  '  were  used  to  preserve  these  products.  .  .  .  When 
finally  satisfied  as  to  the  honest)'  of  these  exhibits,  all 
three  were  promptly  awarded  gold  medals.  .  .  .  No  other 
country  except  France  attempted  to  show  natural  milk 
and  cream.  The  French  exhibits  of  natural  milk  and 
cream  were  in  striking  contrast  with  those  from  the  Unit- 
ed States.  At  the  July  show  there  was  not  a  single  one 
of  these  local  exhibits  which  was  fit  to  use  the  day  after 
reaching  the  grounds,  and  even  in  the  moderate  tempera- 
ture of  the  Ala)7  and  September  shows,  the  French  prod- 
ucts were  all  sour  on  the  second  or  third  day.  But  there 
were  the  natural  products  from  America,  just  as  they 
would  be  delivered  to  consumers  in  New  York  and  Chi- 
cago, still  perfectly  sweet,  a  fortnight  after  being  bottled 
and  after  a  summer  journey  of  three  thousand  or  four 
thousand  miles." 

In  a  personal  letter  to  the  author,  Major  Alvord  states: 
"  The  general  milk  service  of  Europe  in  all  particulars  is 
inferior  to  our  own.  This  is  especially  true  in  France, 
where  it  is  difficult  to  get  natural  milk,  in  the  cities  and 
larger  towns,  which  will  remain  sweet  even  a  few  hours. 
Moreover,  we  are  making  more  rapid  and  substantial  im- 
provements in  this  important  branch  of  pure  food  supply- 
than  anywhere  else  in  the  world." 

It  will  be  seen  that  the  milk  business  is  not  conducted 
on  the  same  basis  in  Europe  as  in  America.  Therefore 
quotations  and  recommendations  for   pasteurization    of 


PRESERVATION    OF   MILK.  103 

milk  made  by  European  observers  have  not  much  appli- 
cation in  America. 

There  can  be  little  doubt  in  the  reader's  mind  as  to 
which  method  of  preserving  milk  is  the  best  to  follow. 
In  the  next  chapter  will  be  given  a  description  of  the 
methods  of  conducting  the  milk  business  in  American 
cities. 


CHAPTER    XIII. 

MARKET   MILK. 

67.  The  great  reduction  in  infant  sickness  and  mor- 
tality that  has  generally  followed  an  improvement  in  the 
milk  supplies  of  a  community  makes  a  knowledge  of  the 
proper  methods  of  producing  and  marketing  milk  of  the 
greatest  importance  to  physicians,  sanitarians,  and  those 
having  the  care  and  feeding  of  infants. 

What  is  wanted  is  a  plentiful  supply  of  fresh  milk 
which  is  in  practically  the  same  condition  as  it  was  in  the 
cow's  udder  as  far  as  contamination  is  concerned,  and  at 
a  price  that  will  put  it  within  the  reach  of  all.  It  is  possi- 
ble to  obtain  such  milk  anywhere  and  at  a  trifling  advance 
over  the  price  charged  for  ordinary  good  milk,  but  not 
without  some  improvement  in  the  methods  of  handling  it. 

In  the  previous  chapter  it  was  shown  that  most  of  the 
changes  in  milk  are  caused  by  bacteria  that  get  into  the 
milk  (1)  with  dust  and  dirt  during  milking,  and  (2)  from 
dirty  dairy  utensils  after  milking,  and  (3)  that  the  great 
increase  in  numbers  is  the  result  of  the  milk  not  being 
cooled  and  kept  cool;  (4)  also  that  the  bacteria  which 
produce  poisons  in  milk  are  apt  to  come  from  stable  filth, 
and  that  these  can  be  kept  out  of  the  milk  by  having  the 
cows,  milker,  and  stable  in  a  sanitary  condition. 

68.  No  idea  of  the  conditions  under  which  milk  is 
produced  or  of  the  number  of  bacteria  it  contains  can  be 


MARKET   MILK.  105 

obtained  by  looking  at  it  or  even  by  tasting  of  it.  Milk 
that  would  cause  acute  illness  may  not  look  or  taste  dif- 
ferent from  wholesome  milk.  It  has  been  found,  how- 
ever, that  milk  containing  few  bacteria  cannot  be  pro- 
duced except  under  the  most  sanitary  conditions;  so 
counting  the  number  of  bacteria  in  a  specimen  of  milk 
will  tell  whether  the  milk  was  properly  cared  for  or  not. 
If  natural  milk  (60)  contains  few  bacteria,  it  was  pro- 
duced under  sanitary  conditions  and  kept  cool.  If  it 
contains  large  numbers,  it  is  dirty  or  was  not  properly 
cooled,  or  both. 

Unfortunately  the  counting  of  bacteria  in  milk  can  be 
done  only  by  those  especially  trained,  and  is  expensive 
work.  The  inability  of  the  average  person  to  determine 
the  condition  of  milk  has  led  to  the  organization  of  milk 
commissions,  usually  made  up  of  disinterested  medical 
men,  who  set  a  standard  of  wholesome  milk  and  issue  a 
certificate  to  any  milkman  whose  milk  is  up  to  this  stand- 
ard, which  he  puts  on  his  milk  bottles.  The  purchaser  is 
then  sure  of  the  quality  of  his  milk.  The  idea  of  a  milk 
commission  originated  with  Dr.  H.  L.  Coit,  of  Newark, 
N.  J.,  and  has  been  applied  to  one  dairy  near  Newark 
with  great  success.  This  dairy  is  under  the  control  of 
the  commission  in  all  of  its  details,  and  a  high  price,  fif- 
teen cents  per  quart,  is  charged  for  the  milk.  The  popu- 
lation in  the  territory  served  by  this  dairy  is  as  a  whole 
well-to-do  and  can  support  it.  In  other  sections  of  the 
country  such  a  high  price  might  be  prohibitory  and  the 
conditions  not  suitable  for  such  a  dairy  organization.  In 
a  large  city  a  great  many  dairies  would  be  needed  to  sup- 
ply enough  milk,  and  to  organize  special  dairies  would 


106  INFANT   FEEDING. 

be  out  of  the  question.  Improvement  can  best  be  ac- 
complished by  working  with  milk  dealers  already  estab- 
lished. An  idea  of  how  this  may  be  done  can  be  had 
from  a  short  history  of  the  organization  of  the  Milk  Com- 
mission in  New  York  City. 

For  several  years  the  author  had  been  studying  the 
milk  supply  of  New  York  in  connection  with  the  subject 
of  home  modification  of  milk  for  infant  feeding.  To  get 
an  idea  of  how  the  milk  business  of  the  city  was  con- 
ducted, a  business  directory  was  taken  and  the  financial 
rating  of  each  milkman  looked  up.  The  bulk  of  the  busi- 
ness was  found  to  be  in  the  hands  of  a  few  dealers — about 
fifty — some  of  whom  were  rated  by  the  commercial  agen- 
cies as  having  over  $1,000,000  invested.  These  dealers 
handled  about  1,250,000  quarts  of  milk  daily. 

A  list  of  questions  was  sent  to  each  of  them,  asking, 
among  other  things,  if  they  sold  milk  to  families  in  bot- 
tles or  not,  and  at  what  price  ;  under  what  conditions  their 
milk  was  produced,  and  what  percentage  of  fat  it  con- 
tained. From  these  answers  and  talks  with  the  milkmen 
who  called,  the  condition  of  the  milk  trade  was  easily  dis- 
covered. It  appeared  that  very  few  of  the  dealers  had 
their  own  cows,  but  bought  their  milk  from  farmers. 
Milk-receiving  stations  called  creameries  are  established 
at  the  railroad  stations  in  dairy  sections,  and  a  number  of 
farmers  bring  their  milk  to  these  stations,  where  it  is 
mixed  and  prepared  for  shipment. 

The  milk  business  is  divided  sharply  into  two 
branches:  (1)  One  selling  milk  in  forty-quart  cans  to  gro- 
cery stores,  restaurants,  etc. ;  and  (2)  the  other  in  bottles 
to  families  direct. 


MARKET    MILK. 


107 


(1)  Price  is  the  first  consideration  in  "  grocery  milk," 
and  the  milk  is  bought  of  the  farmers  at  prices  that  barely 
pay  for  the  cow's  feed  (72).  The  milk  is  then  standard- 
ized— that  is,  adjusted  so  that  it  will  contain  as  nearly  as 
possible  three  per  cent  of  fat  and  twelve  per  cent  of  total 
solids,  the  minimum  quantities  allowed  by  law,  any  excess 


Fig.  23. — Milk  Receiving  Station  or  Creamery. 

of  fat  being  removed  and  sold  as  cream.  "  Grocery  milk  " 
retails  in  New  York  at  from  three  to  four  cents  per 
quart. 

(2)  For  the  milk  intended  for  family  trade  the  farmers 
receive  better  prices  and  more  care  is  expended  on  it. 
Some  dealers  filter  or  clarify  it  (64).  Others  allow  the 
cream  to  rise  and  draw  off  some  of  the  under  milk,  so 


io8 


INFANT   FEEDING. 


that  the  remaining  milk  will  show  more  cream  when  de- 
livered in  bottles  to  the  families. 

The  milk  is  then  bottled  by  machinery  and  packed  in 
cases  containing  cracked  ice.  Much  of  this  milk  is  good ; 
some  of  it  all  that  could  be  desired.  The  average  retail 
price  charged  is  eight  cents  per  quart. 


Fig.  24.— Bottle  Fill 


Many  of  these  dealers  have  spent  considerable  sums 
of  money  trying  to  improve  their  milk,  but  often  they 
have  not  worked  intelligently,  not  knowing  where  to  ex- 
pend to  the  best  advantage.  It  is  not  to  be  expected  that 
they  would  know  how,  as  many  started  as  drivers  of  milk 
wagons  and  know  nothing  of  bacteriology  or  practical 
sanitation. 


MARKET   MILK.  109 

69.  Having  this  information,  the  writer  read  a  paper 
on  "  How  the  Milk  Supply  of  New  York  May  be  Im- 
proved," at  a  meeting  of  the  Medical  Society  of  the 
County  of  New  York,  to  which  the  milkmen  were  invited. 
At  this  meeting  Maj.  H.  E.  Alvord,  chief  of  the  Dairy 
Division  of  the  United  States  Department  of  Agricul- 
ture, and  Prof.  H.  W.  Conn  spoke  of  dairy  conditions  and 
bacteriology,  and  the  milkmen  presented  their  side  of  the 
question. 

A  committee,  with  the  author  as  chairman,  was  ap- 
pointed to  look  into  the  milk-supply  question,  and  the 
present  milk  commission  resulted.  Details  of  the  inves- 
tigations conducted  by  this  committee  will  be  found  in 
the  Medical  Record,  October  19th,  1901. 

The  milk  dealers  were  invited  to  meet  with  the  com- 
mittee, and  many  did.  The  committee  explained  the  ob- 
ject of  the  movement  and  asked  them  how,  in  their  opin- 
ion, the  problem  could  be  best  attacked.  The  dealers 
soon  found  that  the  object  was  to  help  them  and  not  to 
harass  or  burden  them  with  unnecessary  restrictions, 
and  they  took  hold  with  hearty  good-will.  The  standard 
determined  on  for  milk  for  certification  was  not  over 
30,000  bacteria  per  cubic  centimetre,  acidity  not  over  .2 
per  cent,  and  at  least  3.5  per  cent  of  butter  fat.  This  is 
a  high  standard  when  it  is  considered  that  some  of  the 
milk  has  to  be  brought  several  hundred  miles  by  railroad 
during  hot  weather.  At  first  none  of  the  dealers  could 
supply  milk  up  to  the  standard,  but  by  visiting  the  farm- 
ers who  produced  the  milk  and  showing  them  how  to  ar- 
range their  stables,  clean  their  cows,  hands,  and  dairy 
utensils,  it  was  found  that  milk  well  within  the  standard 


no 


INFANT   FEEDING. 


could  be  produced  in  abundance  and  at  a  small  advance 
in  price  over  that  of  the  ordinary  bottled  milk. 

70.  Here  is  a  practical  example  of  progression  in 
methods  of  handling  milk,  furnished  to  the  author  by  a 
large  New  York  milk  company.     The  manager  of  this 

company  originally  started  with 
a  single  milk  wagon  and  de- 
livered milk  to  families  himself, 
dipping  it  out  of  cans.  As 
bottled  milk  began  to  be  han- 
dled, he  and  other  small  deal- 
ers combined  and  established 
creameries  or  bottling  stations 
(68),  and  now  have  a  large 
business  with  families.  This 
company  has  several  bottling 
stations,  at  each  of  which  the 
milk  of  about  twenty  farmers 
is  mixed  and  bottled. 

By  experience  it  had  been 
found  that  the  milk  could  not 
arrive  in  New  York  in  good 
condition  unless  cooled  soon 
after  milking,  so  no  milk  would 
be  received  from  the  farmers 
that  was  warmer  than  6o°  F.  The  cooling  was  done  by 
pouring  the.  milk  over  the  surface  of  a  cooler  containing 
well  or  spring  water. 

One  day  in  the  middle  of  August,  1901,  the  bacteria 
in  the  milk  of  each  farmer  that  supplied  one  of  these 
creameries  were  counted;  the  farmers  were  then  shown 


Fig.  25. — Milk  Cooler  for  Use  with 
Water. 


MARKET   MILK. 


in 


how,  by  cleaning  out  their  stables  better,  wiping  the  cows 
with  a  damp  cloth,  and  keeping  dusty  hay  out  of  the  sta- 
ble during  milking  time,  the  bacteria  in  the  milk  would 
be  reduced  in  numbers;  and  two  or  three  weeks  later  an- 
other count  was  made.  Here  are  the  counts  before  any 
suggestions  were  made,  and  after  they  were  put  into 
effect.  In  some  instances  remarkable  reductions  in 
count  are  shown.  It  cost  no  more  to  produce  the  milk 
at  one  time  than  the  other. 

Bacteria  per  Cubic  Centimetre. 


Farmer. 

Before  changes  were  made. 
Middle  of  August. 

After  changes  were  made. 
About  September  1st. 

No.     i 

44,800 

83,400  morning. 
38,400  night. 
65,000 

32,000 

57,600  morning. 
70,400  night. 
460,800 

5  7S,ooo 
76,800 
63,500 

102,400 

137,000 

99,300 

9,827,000 

121,600 

80,000 

76,800 
159,200 
349,200 

29,300  morning. 

23,600  night. 

41,400  morning. 

37,200  night. 

32,000  morning. 
321,000  night. 

32,000  morning. 
215,000  night. 

12,000  morning. 
172,000  night, 

15,000  morning. 

47,200  night. 
110,200  morning. 

31,400  night. 

27,700  morning. 

59,100  nfght. 

10,200  morning. 

19,200  night. 

18,900  morning. 

19,200  night. 
44,800 

No.      2 

No.     3 

No.    4 

No.     5 .... 

No.     6 

No.     7 

No.     8 

No.  io 

No.  ii 

No.  12 

No.  13 

21,300  morning. 
64,000  night. 
26,700  morning. 
12,800  night. 
210,400  morning. 
S3, 200  night. 
518,400 

No.  14 

No.  15 

No.  16 .  • 

No.  17 

No.  18 

21,400  morning. 
25,600  night. 

ii2  INFANT   FEEDING. 

One  of  these  farmers  was  selected  to  produce  milk  for 
certification,  and  here  are  the  counts  of  his  milk  when 
taken  from  the  delivery  wagon  in  New  York: 


1901 — December 57,100 

December 1 7,000 

December 26,000 

December 36,000 

1902 — January   19,000 

January   11,000 

January   72,000 

January 96,000 

February 150,000 

February 1 7,000  at  farm. 

February 450,000  at  creamery. 

February 12,000 

February 7.75° 

February 2, 700 

March 3,450 

March 3, 700 

March 4, 750 

March 41,000 

April 4,800 

April 4,000 

April 5,200 

April 11 ,000 

May 1,000 

May 20,000 

May 5,8oo 

May 1 7,000 

June 12,000 

June  11,500 

The  high  counts  of  January  and  Feb ruary  were  found 
to  be  caused  by  a  little  water,  used  in  washing  the  bottles 
at  the  creameries,  remaining  in  the  bottles.  After  the 
bottles  were  sterilized  by  steam  before  being  filled  the 
count  became  low.  The  one  high  count  in  March  was 
found  to  be  caused  by  laying  a  new  floor  in  the  creamery. 
Eternal  vigilance  is  the  price  of  low  bacterial  count. 


MARKET   MILK. 


"3 


The  average  price  the  farmer  received  for  this  milk 
during  nine  months  was  3.53^3  cents  per  quart.  During 
June,  1901,  the  price  was  2.57^3  cents,  and  during  No- 
vember, December,  and  January,  1902,  4.06/^  cents.  The 
other  farmers  saw  he  was  making  money,  and  wished  to 
be  allowed  to  furnish  extra  clean  milk  as  fast  as  it  could 
be  sold  in  New  York.  One  cent  a  quart  above  the  prices 
these  farmers  receive  for  their  ordinary  milk,  which  is 


Fig.  26.—  Bottle  Sterilizer. 


used  for  bottling,  will  enabled  them  to  produce  "certi- 
fied milk."  It  is  a  mistake  to  imagine  that  costly  stables 
are  necessary.  Such  milk  can  be  produced  in  the  barn  of 
any  progressive  farmer. 

Undoubtedly  hospitals  and  institutions  could  make 
yearly  contracts  for  this  milk  at  five  cents  per  quart  in 
bulk  and  at  seven  cents  in  bottles.     If  enough  demand 


ii4  INFANT   FEEDING. 

could  be  created  from  the  general  public,  so  the  extra 
expense  of  delivering  small  lots  would  be  reduced,  it 
would  not  sell  at  ten  cents,  the  price  charged,  but  at  eight 
cents  per  quart,  the  present  price  for  good  bottled  milk  in 
New  York.  In  small  towns  and  cities  it  could  be  sold  at 
six  cents,  as  the  freight  charges  into  New  York  are  about 
one  cent  a  bottle,  and  these  would  be  unnecessary  when 
the  milk  was  produced  near  by. 

71.  Grocery  Milk. — It  is  almost  hopeless  to  try  to  im- 
prove "  grocery  milk,"  as  no  one  in  particular  is  responsi- 
ble for  it.  The  price  the  farmer  receives  for  it  (72), 
barely  covering  cost  of  the  cow's  feed,  prohibits  exercise 
of  the  necessary  care  on  his  part,  and  the  continual  open- 
ing of  the  milk  can  in  the  grocery  store  makes  easy  the 
entrance  of  germ-laden  dust  (62).  The  transportation 
from  the  farmer  to  the  store  is  obtained  at  the  lowest 
price,  so  that  conditions  preventing  bacterial  growth  can- 
not be  had.  Legislation  cannot  compel  a  farmer  to  pro- 
duce his  milk  at  a  loss,  and  the  population  that  consumes 
"  grocery  milk "  would  vote  out  of  office  authorities  that 
prohibited  its  sale  or  advanced  its  cost.  Large  numbers 
of  ordinary  dairy  bacteria  in  milk  are  not  harmful  to 
adults.  Buttermilk  contains  millions  of  them  to  the  tea- 
spoonful,  and  no  one  is  afraid  to  drink  it.  The  great  ma- 
jority of  adults  would  rather  run  the  risk  of  using  "gro- 
cery milk "  than  pay  double  price  for  "  certified  milk " 
with  its  to  them  slightly  increased  safety.  With  infants, 
the  increase  of  safety  by  using  "  certified  milk "  is  very 
great,  and  few  parents  would  let  three  or  four  cents  a  day 
additional  cost  prevent  their  purchasing  it  for  their  chil- 
dren, if  they  knew  its  value. 


MARKET   MILK. 


ii5 


72.  Cost  of  Producing  Milk. — The  full  force  of  the 
statements  concerning  "  grocery  milk  "  will  be  appreciated 
by  a  glance  over  the  following  figures,  showing  what 
farmers  receive,  and  the  cost  of  producing  a  quart  of  milk, 
also  the  profit  the  farmer  is  liable  to  make  from  a  cow 
during  a  year. 

According  to  the  New  York  Farmer,  a  dairy  paper, 
the  average  prices  the  farmers  of  New  York  State  have 
actually  received  for  the  milk  shipped  to  New  York  in 
forty-quart  cans  have  been  during 


Cents 
per  quart. 

1897 I.  69I -I.  84I 

1898 I. 735-I.885 

1899 I.879-2.O29 


Cents 
per  quart. 

I9OO 2.084-2.  237 

I9OI I.969-2. I20 


and  the  prices  paid  by  one  of  the  largest  milk-condensing 
companies,  which  requires  a  fairly  clean  milk,  were  dur- 
ing 1901 : 


1901.  Centsf 

per  quart. 

January 3-33X 

February 3-11H 

March 2. 90^ 

April 2.47X 

May 2. 15 

June    1. 72 


1901.  Cents 
'                                       per  quart. 

July 2.04^ 

August 2. 36^4 

September 2. 79^ 

October 3.01 

November 3.22^ 

December 3-33/4^ 


Now  glance  at  the  cost  of  producing  milk. 

73-  The  average  cost  of  the  milk  of  a  herd  of  twenty 
cows  at  the  New  York  (Cornell)  Experiment  Station  for 
a  year  was  .625  cents  per  one  hundred  pounds,  or  1.33 
cents  per  quart.  The  milk  of  one  cow  cost  $1.48  per  one 
hundred  pounds,  or  3.15  cents  per  quart. 

Tests  of  pure-bred  cattle  at  the    Maine,  New  York, 


n6 


INFANT   FEEDING. 


and  New  Jersey  experiment  stations  show  the  following" 
costs : 


Breed. 

Average 

yield  per  year 

in  pounds. 

Average 

per  cent,  of 

Fat. 

Cost  of  100 

pounds  milk. 

Cents. 

Cost 
per  quart 

8,696 
8,215 
6,909 
6.2IO 

5,579 
3,984 

3-97 
3-43 
3.60 
5.20 
5-40 
4.60 

7S.7 
74-7 
78.5 
82.8 

94-7 
94.0 

1.66 

I.59 
I.67 
I.76 

2.06 

2.05 

Individual  cows  of  the  herd  of  the  Wisconsin  Experi- 
ment Station  made  the  following  showing  during  the  year 
1900: 


Breed. 


00'JS 


u!  S  -2 

o  EL  a 


~C ,  -  o 

Sl| 


?    ?  CO 


Grade  Short  Horn 
Grade  Short  Horn 
Grade  Short  Horn 
Grade  Short  Horn 
Grade  Short  Horn 

Grade  Jersey 

Grade  Jersey 

Grade  Guernsey  . . 
Holstein  Friesian  . 
Holstein  Friesian  . 


10,131.74.7 

10,100.0  4. 15 

7,833.04  o 


6,973-2 
7,996.7 
5,775-3 
7,473.o 
6,095.0 

9.561.4 

8.86S.9 


4-2 

4-1 


5-3 

5-5 
3-5 
3.S 


39.60  J 
36.44  I 
38.19 
27.16 
26.22  1 

32. is 

32.27  I 
26.89  ' 
38.21 1 

37-39  ! 


39-0 
36.0 
48.7 
39.1 
32.7 
56.1 
43-1 
44-1 
39-0 
42.1 


0.83 
.76 

1.03 
•83 
•  70 

1.20 
.92 
•94 
.83 
.90 


92.23 
74-00 
41.06 
47-27 
57.48 
49-32 
66.20 
57-03 
52.30 
S4.0S 


79.  S6 

54-43 
Not  given. 
Xot  given. 

20.86 
Not  given. 

57-14 
•07 
Not  given. 
Not  eiven. 


These  ten  cows  netted  $590.97,  or  $59.09  per  cow  dur- 
ing a  year,  or  16  cents  a  day.  In  the  foregoing  costs  of 
milk,  no  allowance  is  made  for  labor,  the  cow's  manure 
being  said  to  be  worth  her  care. 

It  has  been  stated  by  H.  E.  Alvord  that  many  authori- 
ties believe  that  in  the  United  States  one-third  of  the 
cows  are  kept  at  a  loss,  one-third  about  pay  for  them- 
selves, and  one-third  pay  a  profit  to  their  owners.  If  at 
the  experiment  stations,  the  most  scientific  dairymen,  with 
selected  stock,  which  produce  milk  at  less  than  one  cent 


MARKET   MILK.  117 

a  quart,  can  show  a  yearly  profit  of  only  $59.01  per  cow, 
the  other  experiment  station  herds  whose  milk-cost 
ranged  from  1.55  to  2.9  cents  per  quart  would  not  have 
paid  expenses  with  the  same  prices  for  their  products. 
At  the  New  York  Experiment  Station  (Geneva)  it  was 
calculated  the  herd  would  pay  $19.80  per  cow,  if  milk 
sold  at  2%  cents  per  quart. 

With  these  costs  and  profits  obtained  by  experts  with 
selected  cows,  what  can  be  the  ordinary  farmer's  profits 
at  the  prices  he  receives  ? 

Farrington,  reporting  on  a  herd  of  twelve  cows  tested 
on  a  farm  for  a  year  by  experts  from  the  Wisconsin  Ex- 
periment Station,  says:  'The  entire  herd  only  paid  a 
profit  of  $75,  and  three  of  the  twelve  cows  paid  $50  of  this 
amount,  while  the  combined  profit  of  the  other  nine  was 
only  $25.  .  .  .  There  were  three  cows  which  did  not  pro- 
duce milk  enough  to  pay  for  their  feed."  The  daily 
profit  each  cow  paid  was  one  cent. 

Farmers  cannot  be  expected  to  take  additional  care  of 
their  milk  without  extra  compensation.  Higher  prices  to 
the  farmer  is  the  solution  of  the  milk  problem,  and  the 
dealer  should  also  have  extra  compensation  for  any  addi- 
tional labor  and  care  on  his  part. 

74-  Milk  Commissions  Regulations. —  Every  milk 
commission  will  have  to  adapt  its  regulations  to  local  con- 
ditions. No  better  guide  can  be  followed  than  the  "  Fifty 
Dairy  Rules"*  of  the  United  States  Department  of  Agri- 
culture. 

The  following  circulars  sent  out  to  the  milkmen  by 

*  A  copy  of  these  can  be  had  free  of  charge  by  applying  to  the  Secretary  of 
Agriculture.  Washington,  D.  C 


u8  INFANT   FEEDING. 

the  New  York  Commission  may  prove  interesting.  It 
will  be  noticed  that  the  cost  to  the  dealers  for  examina- 
tion of  their  milk  is  as  low  as  one-tenth  of  one  cent  a 
quart,  and  will  be  lower  as  the  output  increases. 

CIRCULARS, 
ist.  "Certified  Milk." 

CIRCULAR  OF  INFORMATION  CONCERNING  THE  REQUIRE- 
MENTS OF  THE  MILK  COMMISSION  OF  THE  MEDICAL 
SOCIETY  OF  THE  COUNTY  OF  NEW  YORK  FOR  "CER- 
TIFIED"  MILK. 

The  Commission  appointed  by  the  Medical  Society  of  the 
County  of  New  York  to  aid  in  improving  the  milk  supply  of  New 
York  City  invites  the  co-operation  of  the  milk-dealers  and  farm- 
ers in  attaining  that  end.  The  sale  of  pure  milk  is  of  advantage 
to  those  furnishing  it,  as  well  as  to  those  who  use  it.  The  Com- 
mission has  undertaken  to  assist  both  consumer  and  producer  by 
fixing  a  standard  of  cleanliness  and  quality  to  which  it  can  certify, 
and  by  giving  information  concerning  the  measures  needful  for 
obtaining  that  degree  of  purity. 

The  most  practicable  standard  for  the  estimation  of  cleanliness 
in  the  handling  and  care  of  milk  is  its  relative  freedom  from  bac- 
teria. The  Commission  has  tentatively  fixed  upon  a  maximum  of 
30,000  germs  of  all  kinds  per  cubic  centimetre  of  milk,  which 
must  not  be  exceeded  in  order  to  obtain  the  indorsement  of  the 
Commission.  This  standard  must  be  attained  solely  by  measures 
directed  toward  scrupulous  cleanliness,  proper  cooling,  and  prompt 
delivery.  The  milk  certified  by  the  Commission  must  contain  not 
less  than  four  per  cent,  of  butter  fat,  on  the  average,  and  have  all 
other  characteristics  of  pure,  wholesome  milk. 

In  order  that  dealers  who  incur  the  expense  and  take  the  pre- 
cautions necessary  to  furnish  a  truly  clean  and  wholesome  milk 
may  have  some  suitable  means  of  bringing  these  facts  before  the 
public,  the  Commission  offers  them  the  right  to  use  caps  on  their 


MARKET   MILK.  119 

milk  jars  stamped  with  the  words,  "  Certified  by  the  Commission 
of  the  Medical  Society  of  the  County  of  New  York."  The  dealers 
are  given  the  right  to  use  these  certificates  when  their  milk  is  ob- 
tained under  the  conditions  required  by  the  Commission  and  con- 
forms to  its  standards. 

The  required  conditions  are  as  follows : 

1 .  The  Barnyard. — The  barnyard  should  be  free  from  manure 
and  well  drained,  so  that  it  may  not  harbor  stagnant  water.  The 
manure  which  collects  each  day  should  not  be  piled  close  to  the 
barn,  but  should  be  taken  several  hundred  feet  away.  If  these 
rules  are  observed  not  only  will  the  barnyard  be  free  from  objec- 
tionable smell,  which  is  always  an  injury  to  the  milk,  but  the 
number  of  flies  in  summer  will  be  considerably  diminished.  These 
flies  in  themselves  are  an  element  of  danger,  for  they  are  fond  of 
both  filth  and  milk,  and  are  liable  to  get  into  the  milk  after  having 
soiled  their  bodies  and  legs  in  recently  visited  filth,  thus  carrying 
it  into  the  milk.  Flies  also  irritate  cows,  and  by  making  them 
nervous  reduce  the  amount  of  their  milk. 

2.  The  Stable. — In  the  stable  the  principles  of  cleanliness 
must  be  strictly  observed.  The  room  in  which  the  cows  are  milked 
should  have  no  storage  loft  above  it ;  where  this  is  not  feasible, 
the  floor  of  the  loft  should  be  tight,  to  prevent  the  sifting  of  dust 
into  the  stable  beneath.  The  stables  should  be  well  ventilated, 
lighted,  and  drained,  and  should  have  tight  floors,  preferably  of 
cement.  They  should  be  whitewashed  inside  at  least  twice  a  year, 
and  the  air  should  always  be  fresh  and  without  bad  odor.  A  suffi- 
cient number  of  lanterns  should  be  provided  to  enable  the  neces-. 
sary  work  to  be  properly  done  during  dark  hours.  There  should 
be  an  adequate  water  supply  and  the  necessary  wash-basins,  soap, 
and  towels.  The  manure  should  be  removed  from  the  stalls  twice 
daily,  except  when  the  cows  are  outside  in  the  fields  the  entire 
time  between  the  morning  and  afternoon  milkings.  The  manure 
gutter  must  be  kept  in  a  sanitary  condition,  and  all  sweeping  and 
cleaning  must  be  finished  at  least  twenty  minutes  before  milking, 
so  that  at  that  time  the  air  may  be  free  from  dust. 

3.  Water  Supply. — The  whole  premises  used  for  dairy  pur- 
poses, as  well  as  the  barn,  must  have  a  supply  of  water  absolutely 


120  INFANT   FEEDING. 

free  from  an)'  danger  of  pollution  with  animal  matter,  and  suffi- 
ciently abundant  for  all  purposes  and  easy  of  access. 

4.  The  Cows. — The  cows  should  be  examined  at  least  twice 
a  year  by  a  skilled  veterinarian.  Any  animal  suspected  of  being 
in  bad  health  must  be  promptly  removed  from  the  herd  and  her 
milk  rejected.  Never  add  an  animal  to  the  herd  until  it  has  been 
tested  with  tuberculin  and  it  is  certain  that  it  is  free  from  disease. 
Do  not  allow,  the  cows  to  be  excited  by  hard  driving,  abuse,  loud 
talking,  or  any  unnecessary  disturbance.  Do  not  allow  any 
strongly  flavored  food,  like  garlic,  which  will  affect  the  flavor  of 
the  milk,  to  be  eaten  by  the  cows. 

Groom  the  entire  body  of  the  cow  daily.  Before  each  milking 
wipe  the  udder  with  a  clean  clamp  cloth,  and  when  necessary  wash 
it  with  soap  and  clean  water  and  wipe  it  dry  with  a  clean  towel. 
Never  leave  the  udder  wet,  and  be  sure  the  water  and  towel  used 
are  clean.  If  the  hair  in  the  region  of  the  udder  is  long  and  not 
easily  kept  clean,  it  should  be  clipped.  The  cows  must  not  be 
allowed  to  lie  down  after  being  cleaned  for  milking  until  the  milk- 
ing is  finished.  A  chain  or  rope  must  be  stretched  under  the 
neck  to  prevent  this. 

All  milk  from  cows  sixty  daws  before  and  ten  days  after  calv- 
ing must  be  rejected. 

5.  The  Milkers. — The  milker  should  be  personally  clean. 
He  should  neither  have  nor  come  in  contact  with  any  contagious 
disease  while  employed  in  milking  or  handling  milk.  In  case  of 
any  illness  in  the  person  or  family  of  an}'  employee  in  the  dairy, 
such  employee  must  absent  himself  from  the  dairy  until  a  physician 
certifies  that  it  is  safe  for  him  to  return. 

Before  milking,  the  hands  should  be  thoroughly  washed  in 
warm  water  with  soap  and  a  nail  brush  and  well  dried  with  a 
clean  towel.  On  no  account  should  the  hands  be  wet  during  the 
milking. 

The  milking  should  be  done  regularly  at  the  same  hour  morn- 
ing and  evening,  and  in  a  quiet,  thorough  manner.  Light-colored 
washable  outer  garments  should  be  worn  during  milking.  They 
should  be  clean  and  dry,  and  when  not  in  use  for  this  purpose 
should  be  kept  in  a  clean  place  protected  from  dust.     Milking 


MARKET   MILK.  121 

stools  must  be  kept  clean.     Iron  stools,  painted  white,  are  recom- 
mended. 

6.  Helpers  other  than  Milkers. — All  persons  engaged  in 
the  stable  and  dairy  should  be  reliable  and  intelligent.  Children 
under  twelve  years  should  not  be  allowed  in  the  stable  during 
milking,  since  in  their  ignorance  they  may  do  harm,  and  from 
their  liability  to  contagious  diseases  they  are  more  apt  than  older 
persons  to  transmit  them  through  the  milk. 

7.  Small  Animals. — Cats  and  clogs  must  be  excluded  from 
the  stables  during  the  time  of  milking. 

8.  The  Milk. — The  first  few  streams  from  each  teat  should 
be  discarded,  in  order  to  free  the  milk  ducts  from  milk  that  has 
remained  in  them  for  some  time  and  in  which  bacteria  are  sure  to 
have  multiplied  greatly.  If  in  any  milking  a  part  of  the  milk  is 
bloody  or  stringy  or  unnatural  in  appearance,  the  whole  quantity 
of  milk  yielded  by  that  animal  must  be  rejected.  If  any  accident 
occurs  by  which  the  milk  in  a  pail  becomes  dirty,  do  not  try  to 
remove  the  dirt  by  straining,  but  reject  all  the  milk  and  cleanse 
the  pail.  The  milk  pails  used  should  have  an  opening  not  exceed- 
ing eight  inches  in  diameter. 

Remove  the  milk  of  each  cow  from  the  stable  immediately 
after  it  is  obtained  to  a  clean  room  and  strain  it  through  a  steril- 
ized strainer. 

The  rapid  cooling -of  milk  is  a  matter  of  great  importance. 
The  milk  should  be  cooled  to  45  °  within  one  hour.  Aeration  of 
pure  milk  beyond  that  obtained  in  milking  is  unnecessary. 

All  dairy  utensils,  including  bottles,  must  be  thoroughly 
cleansed  and  sterilized.  This  can  be  done  by  first  thoroughly 
rinsing  in  warm  water,  then  washing  with  a  brush  and  soap  or 
other  alkaline  cleansing  material  and  hot  water,  and  thoroughly 
rinsing.  After  this  cleansing,  they  should  be  sterilized  with  boil- 
ing water  or  steam  and  then  kept  inverted  in  a  place  free  from 
dust. 

9.  The  Dairy. — The  room  or  rooms  where  the  bottles,  milk 
pails,  strainers,  and  other  utensils  are  cleaned  and  sterilized 
should  be  separated  somewhat  from  the  house,  or  when  this  is 
impossible  have  at  least  a  separate  entrance,  and  be  used  only  for 


122  INFANT    FEEDING. 

dairy  purposes,  so  as  to  lessen  the  danger  of  transmitting  through 
the  milk  contagious  diseases  which  may  occur  in  the  home. 

Bottles,  after  filling,  must  be  closed  with  sterilized  discs,  and 
capped  so  as  to  keep  all  dirt  and  dust  from  the  inner  surface  of 
the  neck  and  the  mouth  of  the  bottle. 

10.  Examination  of  the  Milk  and  Dairy  Inspection. — In 
order  that  the  dealers  and  the  Commission  may  be  kept  informed 
of  the  character  of  the  milk,  specimens  taken  at  random  from  the. 
day's  supply  must  be  sent  weekly  to  the  Research  Laboratory  of 
the  Health  Department,  where  examinations  will  be  made  by  ex- 
perts for  the  Commission;  the  Health  Department  having  given 
the  use  of  its  laboratories  for  this  purpose. 

The  Commission  reserves  to  itself  the  right  to  make  inspections 
of  certified  farms  at  any  time  and  to  take  specimens  of  milk  for 
examination.  It  also  reserves  the  right  to  change  its  standards 
in  any  reasonable  manner  upon  due  notice  being  given  to  the 
dealers. 

After  January  i,  1902,  the  expenses  incurred  in  making  the 
regular  milk  examinations  and  inspections  will  be  borne  by  the 
dealers.  In  fixing  the  charges  each  farm  or  group  of  farms  will 
be  considered  a  unit.  The  Secretary  of  the  County  Medical  So- 
cietv  will  send  bills  to  the  dealers  about  the  middle  of  each  month. 
Prompt  payment  is  requested. 

The  monthly  charges,  which  are  intended  to  cover  all  expenses, 
will  be  as  follows : 

For  each  group  of  farms  sending  daily  less  than  100  quarts^    38.00 
"  "  100  to  200  "  10.00 

"  "  200  to  500  "  12.00 

"  "  over  500  "  15.00 

2d.  "Inspected  Milk." 

CIRCULAR  OF  INFORMATION  CONCERNING  THE  REQUIRE- 
MENTS OF  THE  MILK  COMMISSION  OF  THE  MEDICAL 
SOCIETY  OF  THE  COUNTY  OF  NEW  YORK  FOR  "IN- 
SPECTED"   MILK. 

The  Commission  appointed  by  the  Medical  Society  of  the 
County  of  New  York  to  aid  in  improving  the  milk  supply  of  New 
York  City  has  formulated  the  following  requirements,  affecting 


MARKET    MILK.  123 

the  farms  inspected  by  it  and  the  handling  of  the  milk  obtained  at 
those  farms.  The  Commission  offers  those  dealers  complying 
with  these  requirements  the  right  to  use  caps  on  their  milk  bottles, 
stamped:  "Inspected.  Milk  Commission  Medical  Society, 
County  of  New  York." 

The  requirements  are  as  follows : 

1.  The  Barnyard. 

a)  It  must  contain  no  manure  in  summer  and  none  in  con- 
tact with  the  stable  in  winter. 

b)  It  must  be  well  drained  and  kept  reasonably  clean. 

The  Stables. 

a)  The  ventilation  and  light  must  be  sufficient  for  the  num- 
ber of  cows  stabled,  so  that  the  barn  shall  be  light  and 
the  air  never  close. 

b)  The  floor  shall  be  of  wood  or  cement. 

c)  The  ceiling  shall  be  tight,  if  a  loft  above  is  used. 

d)  Basins,  hand  brushes,  clean  water,  soap  and  clean  towels 
shall  be  provided  in  the  barn  or  adjacent  dairy  room. 

e)  The  stable  shall  be  whitewashed  in  the  fall,  and  in  the 
spring  if  necessary. 

f)  A  sufficient  number  of  lanterns  shall  be  provided  to  allow 
the  milking  to  be  carried  on  properly. 

g)  Clean  the  ceiling  and  sidings  once  a  month, 
h)  The  bedding  shall  be  shavings,  sawdust,  dried  leaves,  cut 

straw,  or  other  material  that  meets  with  the  approval  of 

the  Commission, 
i)  The  soiled  bedding  must  be  removed  daily, 
j)  The  manure  must  be  removed  daily  from  the  stalls  and 

open   manure-gutter.      If  a   covered   manure-gutter   is 

used,  it  must  be  kept  in  a  sanitary  condition, 
k)  The  application  of  land-plaster  or  lime  on  the  floor  daily 

is  recommended. 
1)  Sweep  the  entire  floor  outside  of  the  stalls  daily  at  least  an 

hour  before  milking  is  begun. 

Water  Supply. 

Pure  water  must  be  used  for  all  purposes.     It  must  be 
accessible  and  abundant. 


i24  INFANT   FEEDING. 

4.  The  Cows. 

(a)  Discard  milk  containing  mucus  or  blood  and  that  from  any 

diseased  cow. 

(b)  Reject  milk  from  any  animal  forty-five  days  before  and 

six  days  after  calving. 

(c)  The  food  given  must  be  suitable  both  in  amount  and  kind 

and  must  not  give  a  disagreeable  flavor  to  the  milk. 

(d)  Keep  the  cows  clean  on  flanks,  belly,  udder,  and  tail. 

(e)  Clip  long  hairs  about  udders  and  clip  the  tail  sufficiently 

to  clear  the  ground. 

(f)  The  cows  must  be  kept  from  lying  down  between  the 

cleaning  and  milking.  The  best  means  of  accomplish- 
ing this  is  by  throat  latches. 

(g)  Clean  the  udder  thoroughly  before  milking. 

5.  The  Milkers. 

(a)  No  milker  or  assistant  shall  have  any  connection  with  the 

milk  at  any  stage  of  its  production  if  he  has  any  com- 
municable disease,  or  if  he  has  been  exposed  to  scarlet 
fever,  diphtheria,  typhoid  fever,  or  smallpox. 

(b)  After  having  everything  prepared  for  milking,  thoroughly 

wash  the  hands  with  soap,  water,  and  brush,  so  that  they 
may  be  clean  when  milking  is  begun. 

(c)  The  hands  and  teats  must  be  kept  dry  during  milking.     If 

they  become  moistened  with  milk,  they  must  be  wiped 
dry  with  a  clean  towel. 

(d)  Suitable  clean  outer  garments,  such  as  overalls  and  jump- 

ers, must  be  put  on  before  milking. 

6.  UTENSILS: 

(a)  Strainers,  whether  metal,  gauze,  or  cotton,  must  be  abso- 

lutely clean  when  used  for  straining  milk. 

(b)  All  dairy  utensils  must  be  absolutely  clean  and  free  from 

dust. 

7.  The  Milk. 

(a)  The  milk  must  not  be  adulterated  in  any  way. 

(b)  It  must  average  four  per  cent,  of  butter-fat. 

(c)  Cooling  must  be  begun  within  thirty  minutes  after  the 

milking.     The  temperature  of  the  milk  must  be  reduced 


MARKET   MILK.  125 

to  550  F.  within  two  hours  after  milking  and  to  50°  F. 
within  three  hours  and  kept  below  that  temperature 
until  delivered  to  the  consumer. 
(d)  When  delivered  to  the  consumer  the  milk  must  not  aver- 
age over  100,000  bacteria  per  cubic  centimetre  from 
May  1  st  to  September  30th,  and  not  over  60,000  bacteria 
per  cubic  centimetre  from  October  1st  to  April  30th. 
If  the  Commission's  requirements  are  fulfilled,  the  bac- 
teria will  not  be  in  excess  of  the  number  permitted. 

8.  Inspections. 

(a)  The  farms  which  furnish  "  Inspected  "  milk  must  always 

be  open  to  inspection  by  the  Commission. 

(b)  Samples  of  milk  must  be  regularly  submitted  for  bacterio- 

logical examination  once  a  month. 

For  cooling  the  milk  to  the  best  advantage,  straining 
through  cheese-cloth  or  a  Turkish  towel  into  a  can  placed 
in  ice-water  is  better  than  the  commercial  coolers  (70). 
All  utensils  should  be  simple,  with  tight  seams  (58),  and 
steamed  if  possible  before  using  (58). 

The  necessity  of  rejecting  a  cow  from  a  herd  simply 
because  she  reacts  to  the  tuberculin  test  (55)  is  open  to 
doubt.  A  difference  is  now  being  drawn  between  tuber- 
culin tuberculosis  and  clinical  tuberculosis.  If  only  a 
small  gland  is  affected  the  cow  will  respond  to  the  tuber- 
culin test ;  the  disease  may  not  spread  in  the  body,  and 
the  cow's  milk  will  not  contain  tubercle  bacilli.  When 
clinical  symptoms  of  tuberculosis  appear,  the  cow's  milk 
should  not  be  used  as  food. 

Bacterial  Standard  for  Certified  Milk. — In  the  author's 
opinion  thirty  thousand  bacteria  to  the  cubic  centimetre 
is  a  small  enough  number  to  merit  certification  of  milk. 
If  enough  care  is  taken  to  keep  the  number  as  low  as  this, 
most  putrefactive  bacteria  will  be  kept  out   (54).     The 


126  INFANT   FEEDING. 

precautions  necessary  to  keep  below  this  number  greatly 
increase  the  cost  of  milk  and  defeat  the  object  in  view, 
viz.,  to  place  within  the  reach  of  all  wholesome  milk  at  a 
moderate  price,  as  few  milkmen  can  keep  up  to  a  higher 
standard,  no  matter  what  price  they  obtain,  and  the  high 
price  will  curtail  consumption. 


CHAPTER    XIV. 


METHODS   OF   TESTING   MILK. 


75-  For  most  practical  purposes  it  is  necessary  to  de- 
termine only  the  percentage  of  fat  and  solids  not  fat  in 
milk.  From  (1)  the  percentage  of  fat  and 
(2)  specific  gravity,  the  (3)  solids  not  fat  can 
be  readily  determined.  These  tests  tell 
whether  the  milk  has  been  watered  or 
skimmed  or  both. 

Fat  Test. — The  most  generally  used 
method  of  testing  fat  in  milk  and  cream  is 
that  invented  by  Dr.  S.  M.  Babcock,  of  the 
Wisconsin  Experiment  Station.  In  this  test 
the  ingredients  of  milk  other  than  fat  are 
dissolved  by  sulphuric  acid  in  a  special 
bottle  with  a  graduated  neck.  Hot  water  is 
added,  and  the  bottle  is  whirled  in  a  centri- 
fuge until  the  melted  fat  rises  into  the  neck, 
when  its  percentage  can  be  read. 

The  necks  of  the  bottles  for  milk  testing 
are  graduated  from  o  to  10  per  cent,  with 
subdivisions  of  .2  per  cent,  and  contain  2 
c.c.  between  the  o  and  10  marks,  or  10  per 
cent  of  20  c.c.  If  the  milk  and  melted  fat 
had  the  same  specific  gravity  as  water,  20  c.c.  of  milk 
would  be  used  in  making  a  test.     However,  17.44  c-c-  °f 


Fig.  27. — Babcock 
Milk  Test  Bottle. 
(Farrington  and 
Woll.) 


128 


INFANT   FEEDING. 


milk  are  placed  in  the  bottles,  as  2  c.c.  of  melted  butter 
fat  weigh  but  1.8  grams  and  17.44  c.c.  of  milk  weigh  ten 
times  as  much,  or  18  grams.  The  percentage 
reading  is  thus  by  weight,  not  volume. 

Cream  bottles  are  graduated  from  o  to  35  per 
cent,  with  subdivisions  of  .5  per  cent.  A  little  less 
than  18  c.c.  of  cream  is  placed  in  the  bottle,  as 
this  quantity  weighs  18  gm.,  the  excess  of  fat 
lighter  than  water  offsetting  the  solids  heavier 
than  water  in  the  cream. 

In  making  the  test,  (1) 
the  sample  of  milk  or 
cream  is  mixed  by  gently 
pouring  from  one  vessel 
into  another  two  or  three 
times.  (2)  A  pipette  grad- 
uated for  17.6  c.c.  of  milk 
or  18  c.c.  of  cream  is  used 

\\ffl  for  measuring,  as  this  de- 
livers the  proper  quantities 
into  the  bottle  when  the 
last  drop  is  blown  out  with 
the  breath.  (3)  To  the 
milk  or  cream  in  the  test 
fig.  28.-  bottle  is  added  about 

17.6    c.c. 

pipette.   17.5  c.c.  of  commer- 

( Farring- 

ton  and  cially  pure  sulphuric 
acid,  specific  gravity, 

1 .82.     One  cubic  centimetre 

more  or  less  makes  little  difference.    The  color  at  the  junc- 
tion of  the  milk  with  the  acid  is  greenish  with  pure  milk. 


Fig.  29. 


-Wrong  Way  of  Emptying  Pipette. 
(Farrington  and  Woll.) 


METHODS   OF  TESTING   MILK.  129 

If  formaldehyde  is  present  there  is  a  violet  ring  and  the 
curd  dissolves  slowly.  A  ring  other  than  greenish  sug- 
gests preservatives.  (4)  The  bottle  is  now  gently  shaken 
until  all  the  curd  that  forms  is  dissolved,  care  being  taken 
not  to  allow  any  specks  to  get  into  the  neck.  The 
mixed  milk  and  acid  becomes   very  hot  and  melts  the 


Fig.  30.— Right  Way  of  Emptying  Pipette.     (Farrington  and  Woll.) 

fat.  It  is  always  well  to  make  tests  in  duplicate  to 
allow  for  accidents  during  the  process.  (5)  The  bottles 
are  then  placed  in  a  centrifuge  and  whirled  for  five  min- 
utes. (6)  Boiling  water  is  added  up  to  the  base  of  the 
neck  and  the  bottles  are  whirled  for  a  minute  or  two. 
(7)  Again,  boiling  water  is  added  so  the  melted  butter 


130 


INFANT   FEEDING. 


fat  will  reach  nearly  to  the  top  mark  on  the  scale,  and 
the  bottles  are  again  whirled  for  one  minute.  (8)  Before 
reading  the  percentage  of  fat  it  is  well 
to  pour  some  boiling  water  over  the 
outside  of  the  necks  of  the  bottles  with 
a  pipette  to  be  sure  the  butter  fat  is 
melted.  If  the  acid  was  too  strong  the 
fat  may  appear  charred,  and  if  too  weak 
the  curd  will  not  be  entirely  dissolved. 

In     selecting     Babcock     milk-testing 
machines,  those  that  open  by  removing  a 
cover  on  the  plan  of  that  in 
fig.  3i.-Acid  Measure  the  illustration  will  be  found 

(Farrington  and  Woll.) 

most  convenient. 

The  glassware  should  be  purchased  of 
a  dealer  who  will  guarantee  its  accuracy. 
All  dairy  supply  houses  carry  these  testing 
outfits. 

76.  Specific  gravity. — Before  the  inven- 
tion of  the  Babcock  fat  test,  milk  was  gen- 
erally tested  with  a  lactometer  from  which 
its  specific  gravity  could  be  determined,  but 
this  test  has  little  or  no  value  by  itself.  The 
specific  gravity  of  normal  milk  varies  from 
1.029  to  1.035,  while  that  of  skimmed  milk 
is  as  high  as  1 .036.  The  presence  of  the  fat, 
which  is  lighter  than  water,  makes  the 
specific  gravity  of  normal  milk  less  than 
that  of  skimmed  milk,  the  solids  of  which 
are  heavier  than  water.  Milkmen  soon  found  that  by 
skimming  off  the  cream  and  adding  water  to  the  skimmed 


Fig.  32.  —  Fat  in 
Neck  of  Test  Bot- 
tle.  Reading 
should  be  made  be- 
tween A  and  B  not 
between  A  and  C. 
(Wing.) 


METHODS   OF   TESTING   MILK. 


131 


milk,  the  specific  gravity  of  the  diluted  skimmed  milk 
could  be  made  the  same  as  that  of  normal  milk.  For 
this  reason  the  lactometer  has  little  value  by  itself  for 
testing  milk.  But  if,  in  addition  to  the  specific  gravity 
obtained  from  the  lactometer  reading,  the  percentage  of 
fat  is  determined,  the  total  solids  and  solids  not  fat  in  a 
specimen  of  milk  can  be  quickly  ascertained.  Skimming 
and  watering  of  milk  can  thus  be  readily  detected. 

There  are  two  forms  of  lactometers  in  general  use, 
known  as  the  Board  of 
Health  and  Quevenne's 
lactoriieters.  The  scale 
on  the  Board  of  Health 
lactometer  is  divided 
into  120  degrees,  the 
100  mark  indicating  a 
specific  gravity  of  1.029 
and  the  120  mark  of 
1.035,  which  is  the  range 
for  normal  milk.  As 
100  degrees  on  the  lac- 
tometer scale  equal  a  specific  gravity  of  1.029,  multiplying 
any  degree  on  the  scale  by  .29  will  give  the  specific  grav- 
ity figures  when  1 .0  is  placed  to  the  left  of  the  result. 

The  scale  on  the  Quevenne  lactometer  reads  from  15 
to  40,  and  gives  the  specific  gravity  directly  by  placing  1.0 
to  the  left  of  the  figures  on  the  scale  (77). 

Tables  have  been  published  by  several  chemists  which 
show  the  percentages  of  solids  not  fat  in  milk  for  each 
half  degree  of  specific  gravity  and  each  one-fifth  per  cent 
of  fat,  which  are  exact  enough  for  all  practical  purposes, 


Fig.  33.— Babcock-Milk  Testing  Machine. 


132 


INFANT    FEEDING. 


being  within  a  small  fraction  of  one  per  cent  of  the  results 
obtained  by  weighing  the  solids.  The  tables  of  different 
chemists  show  slight  differences,  which 
probably  result  from  the  use  of  different 
methods  of  analysis  and  weighing.  In 
America  the  table  constructed  by  Bab- 
cock  is  largely  used.  It  is  not  given 
here  because  the  following  simple  rule 
given  by  Farrington  and  Woll  makes  it 
unnecessary. 

Rule:  Divide  the  lactometer  reading 
(Quevenne's  scale)  by  4,  and  add  to  this 
one-fifth  of  the  percentage  of  fat ;  result, 
solids  not  fat.  By  adding  to  this  the 
weight  of  fat,  total  solids  are  obtained 
(28). 

77-  Hozu  to  Use  Lactometers.  —  Mix 
the  sample  of  milk  by  gently  pouring  it 
from  one  vessel  into  another,  so  that  the 
fat  shall  be  uniformly  distributed.  Have 
the  lactometer  dry  and  lower  it  gently 
into  the  milk,  preferably  in  a  hydrometer 
jar.  Always  have  the  milk  at  a  tem- 
perature within  ten  degrees  of  60  °  F. 
Lactometers  combined  with  thermom- 
eters can  be  had  at  any  dairy  supply 
house.     Do  not  allow  over  half  a  minute 

If 
the  Board  of  Health  lactometer  is  used, 
multiply  the  reading  by  .29  to  get  the  Quevenne 
reading.     Then  for  every  degree  of  temperature  above 


Fig.  34. — Quevenne     Lac-  .  ,        ,  «   .  .  . . 

tometer Floating  in  Milk,  to  elapse  before  taking  the  reading 

(Farrington  and  Woll.) 


METHODS   OF   TESTING    MILK.  133 

60 °  F.  add  .1  degree  specific  gravity,  and  subtract  .1  de- 
gree for  each  degree  of  temperature  below  6o°  F.  Milk 
should  not  be  tested  within  three  hours  of  leaving  the 
cow,  as  erroneous  results  are  obtained,  the  reason  for 
which  is  not  known. 

Exa?nple. — A  specimen  of  milk  is  found  to  contain 
four  per  cent  of  fat,  and  the  Board  of  Health  lactometer 
read  1140  at  550  F.,  or  no0  at  65  °  F. 

114  X  .29  =  33.06-  .5  temp,  correction  =  32.56  }  of  Quevenne  scale. 
no  X  .29  =  31.90-f-  .5  temp,  correction  —  32.40  ) 

Place  1 .0  to  the  left  of  these  results  and  remove  the  deci- 
mal point  from  the  degrees,  and  specific  gravity  1.03256 
or  1.0324  is  the  result. 

Per  cent. 
One- fifth    of    the     percentage     of     fat     (4    per 

cent. -^5) 0.8 

One-fourth   of  the  Quevenne   lactometer   reading 

(32.5°-*-  4) +8.12 

8.92  solids  not  fat. 
-f-4-oo  fat. 

12.90  total  solids. 

This  method  is  accurate  for  milks  containing  up  to  6 
per  cent  of  fat. 

78.  In  paragraph  38  will  be  found  complete  analyses 
of  twenty-nine  different  lots  of  mixed  milks,  ranging  by 
slight  percentages  from  3  per  cent  to  5.25  per  cent 
of  fat  and  11.60  per  cent  to  14.94  per  cent  total 
solids. 

79-  Legal  Standards.  —  In  nearly  all  of  the  States 
which  have  dairy  laws  the  legal  requirement  is  that  milk 
shall  contain  at  least  3  per  cent  of  butter  fat  and  12  percent 
of  total  solids.     Some  States  also  require  that  there  shall 


134 


INFANT   FEEDING. 


be  at  least  8  per  cent,  and  others  9.3  per  cent  of  solids  not 
fat,  as  will  be  seen  in  the  following  table: 


State  Standards  for  Dairy  Products. 

In  force  June,  1900.      From  Bull.  26,  U.  S.  Dept.  Agr. ,  Bureau  of  Animal 

Industry. 


District  of  Columbia 

Georgia 

Illinois  ] 

Indiana 

Iowa 

Maine 

Massachusetts 

Massachusetts,  Apr.  and  Sept. 
Michigan 

Minnesota 

New  Hampshire 

New  Jersey 

New  York 3 

North  Dakota 

Ohio3 

Ohio,  May  and  June 

Oregon  3 

Pennsylvania 

(Milk  and    skim-milk  standards 

refer   to  cities  of    second  and 

third  classes.) 

Rhode  Island 

South  Carolina 

Utah 

Vermont 

Vermont,  May  and  June 

Washington 

Wisconsin 


Milk. 


H  °  v 


12.5 

12 

13 

12.5 

12.5 

Sp.  gr. 
1.029-33 

13 

13 

12 

12 

12 

12 

11. 5 

12 

12.5 

Sp.  gr. 

1.029-33 


12.5 

12 


9.0 

8.5 


9.25 

S 


3-5 

3-5 

3 

3 

3 

3 

3-7 

3 


3-5 


2-5 

3 


Skim-Milk. 

Total  solids, 

Per  cent. 


9-3 


9-3 
Sp.  gr.  1.032-37. 


Sp.  gr.  1.038.... 
2.5  p.c.  fat,  6  p.c. 

cream  by  vol.  sp. 

gr.  1.032-37. 


9  p.  c.  solids  not 
fat. 


^ 
.,-* 

'O^- 


20 

I51 
15 


15 


1 5 


1  Condensed  milk  shall  be  made  from  milk  containing  at  least  the  legal  stand- 
ard of  three  per  cent  of  butter  fat  and  evaporated  to  one  third  or  less  of  its 
original  volume. 

2  Coffee  cream  shall  contain  at  least  fifteen  per  cent  of  fat  and  whipping 
cream  twenty-two  per  cent  fat. 

3  Milk  solids  of  condensed  milk  shall  be  in  quantity  the  equivalent  of  twelve 
per  cent  of  milk  solids  in  crude  milk,  of  which  twenty-five  per  cent  shall  be  fat. 


METHODS   OF  TESTING   MILK.  135 

While  many  cows  give  milk  below  these  standards 
(36),  if  found  in  the  possession  of  an  innocent  dealer  it  is 
likely  to  be  condemned  as  watered.  It  should  be  borne 
in  mind  that  a  great  deal  of  milk  that  contains  over  three 
per  cent  of  fat  will  not'  contain  nine  per  cent  solids  not 
fat.  This  will  be  quickly  seen  if  the  percentage  of  fart  is 
subtracted  from  percentages  of  total  solids  in  analyses 
given  in  paragraph  38. 

80.  The  complete  analysis  of  milk  is  a  complicated 
process  and  not  adapted  for  general  use.  The  methods 
of  analysis  adopted  by  the  Association  of  Official  Agri- 
cultural Chemists  are  generally  used  at  the  United  States 
Agricultural  Experiment  Stations.  It  is  well  to  follow 
these  methods,  as  they  represent  the  combined  experience 
of  the  best  chemists  of  America,  and  are  modified  when- 
ever any  improvements  are  worked  out.  They  are  pub- 
lished by  the  United  States  Government,  and  a  copy  can 
be  had  by  sending  five  cents  in  coin  to  the  Secretary  of 
Agriculture,  Washington,  D.  C. 

Full  description  of  methods  used  by  Babcock,  Russell, 
and  Vivian  in  detection  and  separation  of  the  natural 
enzymes  of  milk,  and  in  the  separations  and  estimation  of 
the  nitrogenous  compounds  of  milk  other  than  casein, 
will  be  found  in  the  fourteenth,  fifteenth,  and  sixteenth 
annual  reports  of  the  Wisconsin  Agricultural  Experiment 
Station. 

English  methods  of  analysis  will  be  found  described 
in  "  Richmond's  Dairy  Chemistry"  (Philadelphia,  1899). 

81.  Acidity  of  Milk  is  never  determined  directly, 
but  by  the  addition  of  some  alkaline  solution,  the  neutral 
point  being  determined  by  a  color  indicator,  phenolphtha- 


136 


INFANT   FEEDING. 


lein  being  generally  used  for  this  purpose.  Milk  fresh 
from  the  cow  is  quite  acid  to  phenolphthalein,  but  almost 
neutral  to  litmus.  Heating  fresh  milk,  which  drives  off 
the  gases  it  contains  and  possibly  precipitates  the  acid 
salts  of  calcium,  reduces  the  acidity  greatly,  as  the  follow- 
ing figures  of  Smethan  and  Ashworth  quoted  by  Rich- 
mond show: 

Milk  direct  from  the  cow 26.  7°  acidity. 

Milk  direct  from  the  cow.  after  boiling- 12.2'       " 

Richmond  recommends  calculating  as  lactic  acid  the 
acidity  to  litmus,  and  gives  as  a  reason  the  results  from 
sour  milk  as  follows  r 


in. 


IV. 


Acidity  (to  phenolphthalein) 
Acidity  (to  litmus) 


1.24 
M 


1.89 

1. 14 


1-52 

.86 


1.32 
.56 


82.  For  testing  the  acidity  of  milk  decinormal  alkali 
solutions  are  generally  used,  but  as  it  is  a  delicate  opera- 
tion to  make  these,  and  as  they  deteriorate  on  standing, 
S torch  and  also  Richmond  recommend  the  use  of  lime- 
water,  which  is  almost  exactly  one-twentieth  normal  and 
which  does  not  deteriorate  if  kept  for  any  length  of  time, 
provided  some  lime  is  left  in  the  bottom  of  the  bottle. 
As  the  bottle  becomes  empty,  all  that  is  necessary  is  to 
add  more  distilled  or  rain  water. 

Lime- Water. — Get  from  any  grocery  store  an  ounce 
or  so  of  lime;  add  a  pint  of  water,  and  stir  thoroughly. 
Allow  the  undissolved  lime  to  settle,  and  pour  off  the 
cleat  lime-water,  which  will  contain  an)'  potassium  or  so- 
dium that  may  have  been  present  in  the  lime.  Do  this 
several  times.     Now  pour  on  a  quantity  of  distilled  water, 


METHODS   OF   TESTING    MILK. 


137 


depending  on  the  sized  bottle  the  lime-water  is  kept  in, 
and  cork ;  when  the  lime  has  settled  so  the  water  is  clear, 
it  is  ready  to  be  used  and  may  be  removed  as  wanted 
with  a  pipette,  as  will  be  described  presently. 

An  easy  way  to  test  the  acidity  of  milk  is:  (1)  First  mix 
the  milk  thoroughly,  and  (2)  with  a  graduated  1  c.c.  pi- 
pette, such  as  is  used  in  measuring  urine,  or  Fehling's 
sugar-test  solution,  place  1  c.c.  of  the  milk  in  a  small  evap- 
orating dish  or  test-tube.  (3)  To  this  add  one  drop  of  an 
alcoholic  solution  of  phenolphthalein  (1  gm.  to  30  c.c. 
alcohol).  (4)  With  another  1  c.c.  pipette  add  drop  by 
drop  clear  lime-water,  and  shake  the  tube  to  mix  thor- 
oughly, until  the  milk  is  colored  a  faint  pink.  Now  note 
how  many  .1  c.c.  of  lime-water  were  used. 


I  c.c. 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 

I  " 


milk  and  phenolphthalein  colored  by  o 


"       1 

1 

"       1 

"       1 


.  I  c.c. 

lime-water 

.045  p.c. 

.2     " 

" 

•°9 

■  3    " 

1 ' 

■135 

•  4    " 

" 

.180 

•  5 

" 

.225 

.6    " 

" 

.270 

•7 

" 

•  315 

.8    " 

" 

.360 

■9    " 

" 

.405 

.0    " 

" 

•  45° 

.  1    *' 

* ( 

■  495 

.2    " 

' ' 

.540 

3    " 

" 

085 

■  4    " 

" 

.630 

5    " 

" 

.675 

acid. 


A  simple  rule  is;  Multiply  0.0045,  the  weight  in  grams 
of  lactic  acid  neutralized  by  1  c.c.  lime-water,  by  the  num- 
ber of  cubic  centimetres  of  lime-water  used,  and  divide 
by  100,  which  gives  the  percentage  of  acidity. 

Farrington  has  devised  an  alkaline  tablet  for  use  in 
testing  acidity  of  milk.     One  of  these  tablets,  which  also 


138  INFANT   FEEDING. 

contains  phenolphthalein,  is  to  be  dissolved  in  one  ounce 
or  30  c.c.  of  distilled  or  rain  water.  If  one  volume  of 
milk  is  faintly  colored  pink  by  an  equal  volume  of  this 
solution,  it  contains  1.1  per  cent  acid;  colored  by  2  vol- 
umes, 0.2  per  cent  acidity,  and  so  on.  These  tablets, 
which  are  carried  by  many  dairy  supply  houses,  have  re- 
cently been  put  up  for  use  of  physicians  and  families 
under  the  name  of  "  ideal  milk  testers."  Many  of  the 
wholesale  druggists  have  them. 

It  should  be  remembered  that  these  methods  of  deter- 
mining acidity  are  only  relatively  correct.  No  exact 
method  has  been  devised.  Degrees  of  acidity,  a  term 
used  in  England,  means  the  number  of  cubic  centimetres 
of  decinormal  alkali  needed  to  neutralize  100  c.c.  of  milk. 
Each  degree  corresponds  to  0.009  Per  cent  lactic  acid. 

83.  Preservatives  in  milk  are  not  uncommon,  espe- 
cially in  summer,  in  country  towns  and  small  cities  where 
milk  is  not  inspected,  and  even  in  large  cities  some  of  the 
milk  is  not  free  from  them.  In  another  place  (63)  the 
composition  of  the  principal  preservatives  now  on  the 
market  is  given,  but  as  new  preparations  are  likely  to  ap- 
pear from  time  to  time  no  detailed  method  of  detecting 
each  will  be  given,  but  one  broad  method  that  will  cover 
them  all ;  viz.,  place  a  few  cubic  centimetres  of  milk  in  a 
test-tube,  plug  with  cotton,  and  keep  it  at  a  temperature 
about  8o°  to  900  F.  This  may  be  done  by  setting  the 
tube  in  a  cup  of  tepid  water.  If  the  milk  does  not  sour 
or  otherwise  change  in  twenty-four  hours,  either  the  ad- 
dition of  preservatives  or  pasteurization  should  be  sus- 
pected. Formaldehyde  can  readily  be  detected  in  mak- 
ing the  Babcock  milk  test   (75),  or  by  mixing  equal  parts 


METHODS    OF   TESTING   MILK.  139 

of  milk  and  water  in  a  test-tube  and  adding,  so  as  to  not 
mix,  a  little  concentrated  sulphuric  acid.  A  violet  ring  at 
the  junction  of  the  acid  and  milk  indicates  formaldehyde. 
C.  P.  sulphuric  acid  will  not  answer  unless  a  minute 
quantity  of  ferric  chloride  is  added. 

84.  Sterilized  Milk  may  be  detected  by  first  adding 
a  starch  and  iodide-of-potassium  solution,  and  then  a  drop 
or  two  of  dilute  peroxide  of  hydrogen.  Milk  heated 
above  1750  F:  remains  unchanged;  fresh  milk,  or  milk 
not  heated  to  1750  F.  is  colored  blue.  This  is  S torch's 
test. 

To  make  the  test:  Add  1  mgm.  cornstarch  to  200  c.c. 
water,  and  boil.  Now  add  5  mgm.  potassium  iodide  and 
filter  after  the  flocculent  matter  has  settled. 

To  a  mixture  of  one  part  of  milk  and  two  parts  of  the 
starch-iodide  potassium  solution,  add  one  or  two  drops  of 
a  dilute  (1  :  10)  solution  of  peroxide  of  hydrogen.  This 
test  should  be  performed  with  fresh  milk  to  get  an  idea  of 
how  it  acts,  before  testing  heated  milk. 

85.  Preservation  of  Samples  of  Milk. — It  is  some- 
times inconvenient  to  test  a  sample  of  milk  for  several 
days  after  it  is  obtained,  or  it  may  be  necessary  to  send 
the  sample  away  by  mail  or  otherwise.  In  such  cases 
add  a  few  drops  of  formaldehyde  and  fill  the  bottle  up  to 
the  cork,  which  should  be  tied  in.  If  the  bottle  is  not  full 
the  milk  will  churn  and  butter  will  form. 


CHAPTER    XV. 

BACTERIOLOGICAL    EXAMINATION   OF   MILK.* 

In  order  that  a  bacteriological  examination  of  milk 
may  be  made  which  shall  have  any  significance  as  indi- 
cating the  wholesomeness  or  unwholesomeness  of  milk,  it 
is  necessary  to  know  at  the  outset  as  much  as  possible  in 
regard  to  the  relation  of  various  milk  bacteria  to  health. 
Upon  this  subject  unfortunately  we  are  as  yet  in  consid- 
erable ignorance.  The  few  facts  which  we  know  may  be 
briefly  summarized. 

Diseases  Attributed  to  Milk. 

It  is  certain  that  some  well-known  diseases  are  occa- 
sionally distributed  by  milk. 

86.  Tuberculosis. — This  disease  is  much  more  com- 
mon in  childhood  than  was  believed  a  few  years  ago.  It 
is  a  well-known  fact  that  cows  suffer  quite  largely  from 
tuberculosis,  and  that  the  milk  which  such  cows  produce 
is  sometimes  contaminated  with  tubercle  bacilli.  It  is 
generally  believed  that  such  milk,  if  used  as  a  food  by 
infants,  may  give  rise  to  tuberculosis  in  the  child.  There 
is,  however,  at  the  present  time  a  considerable  difference 
of  opinion  as  to  the  extent  of  the  danger  to  the  child 
from  this    source.      Whereas  some  are  quite  convinced 

*  This  chapter  has  been  prepared  by  Prof.  H.  \V.  Conn,  of  Wesleyan 
University. 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     141 

that  the  danger  is  very  great  and  that  a  considerable  por- 
tion of  the  infantile  tuberculosis  is  attributable  to  milk, 
there  are  others  that  regard  the  danger  as  not  very  great. 
There  seems  to  be  sufficient  evidence  to  prove  that  the 
child  may  acquire  tuberculosis  from  this  source,  although 
we  do  not  have,  at  present,  sufficient  evidence  to  indicate 
how  great  the  danger  may  be.  It  is  well  to  remember, 
however,  that  the  tubercle  bacillus  does  not  multiply  in 
the  milk,  and  if  the  milk  from  one  tuberculous  cow  is 
mixed  with  milk  from  a  number  of  other  healthy  animals, 
the  final  product  which  is  given  to  the  child  as  food  is 
quite  likely  to  be  diluted  to  such  an  extent  that  the  tu- 
bercle bacilli,  even  though  dangerous,  are  not  present  in 
sufficient  numbers  to  produce  much  trouble. 

87.  Typhoid  Fever.  —  Perhaps  typhoid  fever  is  the 
disease  that  has  been  most  frequently  distributed  by  milk. 
It  is  at  all  events  the  one  in  regard  to  which  we  have  the 
greatest  amount  of  evidence.  The  number  of  typhoid 
epidemics  that  have  been  positively  traced  to  milk  is  now 
very  great.  There  are  scores  of  instances  where  a  com- 
munity suffers  from  an  epidemic  of  typhoid  of  a  more  or 
less  serious  character,  and  where  practically  every  case  of 
the  disease  may  be  traced  to  milk  from  a  certain  source. 
An  outbreak  of  a  typhoid-fever  epidemic  in  any  commu- 
nity renders  the  milk  suspicious,  and  the  milk  is  the  first 
point  for  investigation.  The  cow  herself  does  not  suffer 
from  typhoid  fever,  and  the  typhoid  bacilli  which  get  into 
the  milk  must  come  from  a  different  source  subsequent 
to  the  time  when  the  milk  is  drawn  from  the  cow.  This 
may  be  from  a  milker,  who  is  recovering  from  or  coming 
down  with  typhoid  fever ;  it  may  be  from  the  water  of  a 


142  INFANT   FEEDING. 

well  which  has  become  contaminated  with  typhoid  de- 
jecta, or  it  may  be  some  other  secondary  source.  As  a 
rule,  however,  it  is  believed  that  the  contamination  is 
either  from  a  typhoid  patient,  or  some  one  who  has  in 
some  way  come  in  contact  with  a  typhoid  patient,  or  with 
typhoid  contaminated  water.  Unlike  the  tubercle  bacil- 
lus, the  typhoid  bacillus  is  capable  of  multiplying  rapidly 
in  milk.  The  result  is  that  milk  contaminated  with  ty- 
phoid bacilli  is  far  more  dangerous  than  milk  contami- 
nated with  tubercle  bacilli.  A  few  organisms  that  find 
entrance  at  the  outset  have  an  opportunity  of  developing 
rapidly  before  the  milk  is  consumed,  and  the  consumer 
swallows  milk  that  contains  typhoid  bacteria  in  perhaps 
very  large  numbers.  The  result  is  that  the  danger  of 
typhoid  from  typhoid-contaminated  milk  is  very  great, 
and  the  typhoid  epidemics  from  such  a  source  are  apt  to 
be  violent.  It  rarely  does  any  immediate  good  to  trace  a 
typhoid  epidemic  to  milk  from  a  given  source.  The  milk 
is  contaminated  usually  only  for  a  day  or  two,  and  by  the 
time  the  epidemic  has  appeared  and  it  has  been  possible 
to  trace  it  to  milk  from  a  given  source,  the  contamination 
at  that  source  has  long  since  passed,  so  that  nothing  fur- 
ther can  be  done  to  check  the  development  of  the  epi- 
demic in  this  direction.  It  is,  of  course,  an  advantage  to 
introduce  general  sanitary  precautions  in  the  farm  pro- 
ducing the  milk,  but  no  particular  typhoid  epidemic  due 
to  milk  has  been  checked  by  the  discovery  of  its 
source. 

88.  Scarlet  Fever  and  Diphtheria.  —  These  two  dis- 
eases are  occasionally  distributed  by  the  milk  supply, 
although  our  knowledge  in  regard  to  them  is  at  present 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     143 

somewhat  fragmentary.  We  do  not  positively  know 
whether  the  cows  themselves  suffer  from  these  diseases 
in  such  a  way  as  to  contaminate  their  milk  with  the  bac- 
teria in  question.  We  do  know,  however,  that  milk  may 
become  contaminated  with  the  infectious  material  of 
both  of  these  diseases  subsequent  to  the  milking,  and  that 
sometimes  such  milk  is  the  source  of  distribution  of  both 
of  these  diseases.  The  milk  is,  therefore,  one  of  the  fac- 
tors to  be  guarded  against  in  the  case  of  epidemics  of 
diphtheria  and  scarlet  fever,  but  beyond  such  simple  facts 
our  knowledge  upon  this  matter  is  rather  scanty. 

89,  Dia7rrhoeal  Diseases. — In  regard  to  the  kind  of 
bacteria  which  produce  these  difficulties,  we  are  as  yet  in 
almost  complete  ignorance.  There  are  quite  a  number  of 
species  of  bacteria  found  in  milk  that  have  been  demon- 
strated by  bacteriologists  to  be  capable  of  producing  cer- 
tain poisonous  secretions  as  the  result  of  their  growth. 
If  these  bacteria  should  grow  in  abundance  in  milk  or  in 
the  intestine  of  the  child,  it  is  quite  certain  that  they 
would  produce  toxic  products,  and  such  products  would 
naturally  produce  intestinal  disturbances.  It  is  also  a 
fact  that  the  intestinal  contents  of  children  suffering  from 
such  troubles  show  a  variety  of  fermentative  changes,  a 
putrefaction  of  some  sort  being  extremely  common.  It  is 
therefore  probable  that  it  is  some  of  the  micro-organisms 
which  produce  putrefaction  that  are  responsible,  in  con- 
siderable degree,  for  these  intestinal  troubles.  But 
beyond  some  such  general  suggestions  as  these,  our  bac- 
teriologists as  yet  are  unable  to  make  any  very  definite 
statements  concerning  the  relation  of  bacteria  to  infan- 
tile intestinal  disease. 


144  INFANT   FEEDING. 

Value  of  Bacterial  Examination  of  Milk. 

90.  Recognizing  these  facts,  the  question  arises  as  to 
whether  a  bacteriological  examination  of  milk  for  the 
purpose  of  determining  its  healthful  qualities  is  possible 
and  practicable.  A  bacteriological  examination  of  drink- 
ing-water has  proved  extremely  useful  as  a  means  of  as- 
sisting in  determination  of  the  healthfulness  of  drinking- 
water,  although  not  in  itself  wholly  satisfactory.  It  was 
quite  natural  that  the  methods  of  bacteriological  examina- 
tion which  were  first  used  in  the  study  of  water  should  be 
transferred  directly  to  the  study  of  milk.  The  examina- 
tion of  water  has  consisted  in  the  past  chiefly  in  deter- 
mining the  number  of  bacteria  that  are  present  in  a  cubic 
centimetre  of  water,  and  drawing  a  conclusion  as  to  the 
suspicious  nature  of  the  water  from  the  number  of  bacte- 
ria that  are  present  in  a  cubic  centimetre  of  water.  In 
more  recent  years  there  has  been  a  further  attempt 
slightly  to  differentiate  the  species  of  bacteria  that  are 
found.  This  method  of  quantitative  bacteriological  anal- 
ysis has  also  been  applied  to  milk  as  a  means  of  suggest- 
ing conclusions  as  to  the  healthfulness  of  milk.  But 
when  the  method  is  applied  it  is  found  quite  unsatisfac- 
tory, because  the  results  obtained  are  totally  different 
from  those  obtained  in  the  study  of  water.  So  unlike  are 
these  results  that  the  two  problems  appear  to  be  wholly 
unlike. 

In  the  first  place,  the  number  of  bacteria  found  in 
milk  is  quite  incomparable  with  that  found  in  any  sam- 
ples of  water.  Whereas  a  sample  of  water  containing  a 
few  thousand  bacteria  per  cubic  centimetre  is  imm  „di- 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     145 

ately  regarded  as  suspicious,  it  is  a  certain  fact  that  many 
a  sample  of  milk  which  is  perfectly  wholesome  contains 
bacteria  by  hundreds  of  thousands  and  possibly  by  mil- 
lions. A  comparison  of  the  number  of  bacteria  in  water 
and  milk  will  show  in  water  the  presence  of  a  few  hun- 
dreds per  cubic  centimetre,  and  in  milk  the  presence  of 
many  thousands,  hundreds  of  thousands,  or  occasionally 
millions.  Even  when  compared  to  sewage,  from  the 
standpoint  of  the  number  of  bacteria,  milk  proves  to  be 
surprisingly  bad.  The  milk  that  is  supplied  to  our  cities 
frequently  contains  more  bacteria  than  is  present  in  the 
city's  sewage,  and  in  the  case  of  unusually  bad  samples  of 
milk  the  number  of  bacteria  outnumbers  that  which  is 
found  in  the  worst  sewage. 

Manifestly  the  interpretations  of  the  numbers  of  bac- 
teria as  found  in  milk  and  in  water  cannot  be  the  same. 
It  is  certainly  not  to  be  inferred  that  milk  is  a  more  un- 
healthful  product  than  sewage  because  it  contains  a  larger 
number  of  bacteria.  The  use  of  sewage  as  drinking-water 
would  be  disastrous,  but  milk  that  contains  many  more 
bacteria  is  used  constantly  without  appreciable  injury. 
The  determination  of  the  number  of  bacteria  does  not  de- 
termine the  wholesomeness  of  milk,  and  the  interpreta- 
tion of  the  results  in  the  study  of  milk  is  quite  different 
from  their  interpretation  in  the  study  of  water.  We  can- 
not condemn  a  sample  of  milk  upon  the  same  bacterio- 
logical grounds  as  those  which  force  us  to  condemn  a 
sample  of  water. 

The  presence  of  small  numbers  of  bacteria  does  not 

necessarily  mean  that  the  milk  is  wholesome,  for  among 

the  small  number  there  may  be  pathogenic  forms  which 
10 


1 46  INFANT   FEEDING. 

are  distinctly  injurious.  On  the  other  hand,  the  pres- 
ence of  large  numbers  does  not  mean  that  the  milk  is 
necessarily  unwholesome,  for,  if  this  large  number  of  bac- 
teria contains  only  harmless  or  useful  forms,  their  pres- 
ence is  not  detrimental.  What,  then,  is  the  value  of  a 
counting  of  the  number  of  bacteria  in  milk? 

Bacteriologists  have  learned  that  the  number  of  bacte- 
ria in  any  sample  of  milk  is  dependent  upon  two  factors. 
First,  care  in  the  dairy.  Second,  the  care  in  transporta- 
tion and  in  using  cleanly  vessels  and  low  temperatures. 
Milk  produced  in  a  dirty  barn  will  contain  larger  num- 
bers of  bacteria  than  milk  from  a  clean  barn,  and  the 
same  general  fact  is  true  in  connection  with  the  methods 
in  transportation.  Hence  it  is  that  the  bacteria  count 
will  enable  us  to  determine,  with  considerable  degree  of 
accuracy,  the  question  of  the  cleanliness  of  the  dairy  from 
which  the  milk  was  originally  derived,  and  the  care  which 
has  been  given  the  transportation  of  the  milk.  If  it  is 
found  that  milk  contains  bacteria  in  large  numbers — sev- 
eral millions  per  cubic  centimetre — by  the  time  it  is  ready 
for  distribution,  the  inference  is  drawn  that  it  has  been 
placed  under  conditions  which  should  be  condemned. 
Either  the  original  dairy  failed  to  pay  proper  attention  to 
cleanliness,  or  those  concerned  in  the  transportation  of 
the  milk  have  been  careless  in  their  work.  If,  on  the 
other  hand,  the  milk  is  found  to  contain  a  small  number 
of  bacteria,  the  conclusions  are  that  the  conditions  have 
been  satisfactory. 

Now,  while  it  is  true  that  milk  that  contains  a  small 
number  of  bacteria  may  perhaps  contain  pathogenic  bac- 
teria and  thus  be  dangerous,  nevertheless  in  the  majority 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     147 

of  cases  milk  which  has  been  so  carefully  handled  that 
the  number  of  bacteria  has  been  kept  low  has  not  been 
brought  into  a  condition  where  it  is  likely  to  be  contami- 
nated with  pathogenic  germs.  Only  the  dairyman  who 
takes  care  to  protect  his  milk  will  be  able  to  keep  the  bac- 
teria reduced  to  low  numbers,  and  such  a  dairyman  is  one 
also  who  will  be  quite  sure  to  guard  his  milk  from  con- 
tamination by  pathogenic  bacteria.  On  the  other  hand, 
the  presence  of  large  numbers  of  bacteria  suggests  care- 
lessness, and  indicates,  therefore,  that  there  is  a  greater 
opportunity  for  the  entrance  into  the  milk  of  mischievous 
bacteria.  Hence  it  is  that  while  the  presence  of  large 
numbers  of  bacteria  does  not  necessarily  mean  that  the 
milk  is  unwholesome,  it  renders  us  suspicious  of  condi- 
tions at  its  source  and  of  the  methods  adopted  in  its 
transportation. 

It  is  difficult,  perhaps  impossible,  to  fix  upon  any 
standard  as  to  the  number  of  bacteria  which  wholesome 
milk  may  contain.  Should  we  condemn  milk  when  it 
contains  ten  thousand,  thirty  thousand,  one  hundred 
thousand,  or  a  million  bacteria  per  cubic  centimetre? 
The  question  cannot  be  answered,  because  the  answer 
will  depend  upon  conditions  and,  to  a  large  extent,  upon 
the  season  of  the  year.  It  is  at  present  impracticable  to 
insist  upon  any  definite  standard  at  any  season  of  the 
year  for  the  general  milk  supply.  It  is  true  that  in  some 
cities  a  bacteriological  standard  has  been  set  for  a  certain 
class  of  milk.  Sometimes  this  standard  has  been  set  at 
ten  thousand  per  cubic  centimetre,  sometimes  at  thirty 
thousand  per  cubic  centimetre.  Such  standards  are  prac- 
tical only  for  special  cases,  and  have  been  used  only  when 


148  INFANT    FEEDING. 

some  special  dairy  or  milk  dealer  wishes  to  furnish  a  spe- 
cial product  and  receive  an  advanced  price  for  the  same. 
It  is  useful  for  the  general  plan  of  producing  "certified 
milk,"  mentioned  elsewhere  in  this  work.  But  for  the 
general  supply  of  a  large  city,  no  standard  can  be  insisted 
upon  at  the  present  time,  without  excluding  most  of  the 
milk  in  the  summer  season. 

From  all  these  facts  it  will  follow  that  before  a  bacteri- 
ological examination  of  market  milk  can  be  satisfactory, 
it  must  be  possible  to  do  something  more  than  determine 
simply  the  numbers  of  bacteria.  Some  method  must  be 
determined  by  which  the  different  types  of  bacteria  can 
be  differentiated  from  each  other,  so  that  we  may  know 
how  many  of  the  suspicious  organisms  are  present  and 
how  many  are  perfectly  normal  and  probably  wholesome. 
The  question  whether  such  a  differentiation  is  possible 
has  never  been  as  yet  thoroughly  discussed,  and  hitherto 
no  attempt  has  been  made,  in  all  of  the  bacteriological 
analyses  of  market  milk,  to  separate  the  abnormal  from 
the  normal  types,  or  to  determine  to  what  extent  this  im- 
mense number  of  micro-organisms  may  be  perfectly 
wholesome  and  to  what  extent  they  are  likely  suspicious. 
Is  such  a  differentiation  possible? 

Differentiation  of  Types  of  Milk  Bacteria. 

91.  In  the  first  place,  we  must  notice  that  there  is  at 
present  no  practical  possibility  of  detecting  in  milk  the 
presence  of  the  bacteria  causing  tuberculosis,  scarlet  and 
typhoid  fevers,  or  diphtheria.  The  tubercle  bacillus  can 
be  found  in  milk  by  proper  tests,  but  the  method  is  so 
difficult  as  to  render  it  useless  as  a  means  of  determining" 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     149 

the  wholesomeness  of  milk.  It  has  been  hitherto  quite 
impossible  to  detect  typhoid  bacilli  in  milk,  and  at  pres- 
ent there  seems  to  be  no  prospect  of  success  in  this  line. 
The  same  is  true  in  regard  to  the  diphtheria  bacillus, 
although  the  diphtheria  bacillus  may  be  detected  in  milk. 
The  cause  of  scarlet  fever  is  unknown,  and  there  are  thus, 
no  bacteriological  methods  as  yet  within  our  reach  which 
enable  us  to  detect  in  milk  the  bacteria  which  produce 
either  of  these  four  diseases.  Inasmuch  as  we  do  not 
know  positively  the  cause  of  the  diarrhceal  diseases,  it  is 
of  course  evident  that  bacteriological  methods  will  not 
enable  us  to  detect  with  any  certainty  whether  the  bacte- 
ria that  produce  them  are  present  in  milk  or  not.  Hence 
it  follows  that  bacteriological  analysis  of  to-day  will  not 
enable  us  to  detect  satisfactorily  the  presence  in  milk  of 
the  exciting  cause  of  any  of  the  diseases  most  commonly 
distributed  by  milk. 

Nevertheless  a  partial  differentiation  of  the  milk  bac- 
teria is  quite  feasible.  To  understand  this  it  will  be  nec- 
essary to  mention  the  chief  types  of  bacteria  which  are 
found  in  normal  milk,  referring  to  their  action  upon  milk 
and  their  probable  relation  to  health.  The  number  of 
species  of  bacteria  present  in  milk  is  very  great,  and  very 
little  is  known  about  the  significance  of  most  of  them. 
We  can,  however,  recognize  among  these  bacteria  three 
chief  types  which  are  readily  distinguished  from  each 
other,  and  which  probably  have  quite  a  different  relation 
to  the  problems  of  the  healthfullness  of  milk. 

92.  (1)  Lactic  Bacteria. — These  are  the  most  common 
bacteria  in  milk  which  is  a  few  hours  old,  although  in 
freshly  drawn  milk  they  are  frequently  not  very  numer- 


1 5o  INFANT   FEEDING. 

ous.  There  are  several  types  of  lactic  bacteria,  differing 
from  each  other  in  more  or  less  important  particulars.  In 
milk  in  the  United  States  there  are  three  or  four  species 
which  are  particularly  common  and  may  be  regarded  as 
lactic  bacteria  par  excellence.  The  chief  of  these,  B.  acidi 
lactici,  is  found  widely  distributed,  not  only  in  the  differ- 
ent parts  of  the  United  States,  but  also  in  the  countries 
of  Europe. 

In  their  action  upon  milk  these  bacteria  prove  very 
troublesome,  since  they  cause  its  souring  and  acid  cur- 
dling (37).  To  keep  the  milk  sweet  it  is  therefore  desir- 
able that  their  numbers  should  be  kept  as  low  as  possible. 
As  relates  to  their  influence  upon  the  wholesomeness  of 
milk,  however,  it  seems  quite  probable  that  they  are  not 
detrimental  (52).  Milk  which  does  not  contain  lactic 
bacteria  is  liable  to  varied  putrefactive  fermentations, 
which  are  prevented  by  the  development  of  the  lactic-acid 
bacteria.  Moreover,  there  are  reasons  for  believing  that 
their  presence  in  the  intestine  is  advantageous  rather 
than  detrimental.  At  all  events  there  is  no  evidence  to 
indicate  that  the  normal  lactic  bacteria  render  the  milk 
unwholesome.  Milk  with  a  moderate  number  of  lactic 
bacteria  is  probably  less  liable  to  produce  intestinal  dis- 
turbances than  milk  which  contains  other  types  of  bacte- 
ria and  no  lactic  organisms.  The  presence  of  lactic  bac- 
teria, therefore,  will  suggest  a  speedy  souring  of  the  milk, 
but  will  not  give  any  suspicion  as  to  its  being  unwhole- 
some as  a  food. 

93.  (2)  Bacteria  Producing  A  Idtiminoid  Decomposi- 
tion.—The  decomposition  of  albuminoid  bodies  fre- 
quently gives  rise  to  putrefactive  products.     We  know 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     151 

nothing  positive  as  yet  as  to  the  effect  of  such  decomposi- 
tion products  in  our  foods,  although  it  is  known  that 
some  of  the  products  arising  from  such  decomposition  are 
toxic  in  nature.  It  would  seem  most  probable  that  the 
products  of  albuminoid  putrefaction  will  be  unwholesome 
either  in  the  food  we  eat,  or  in  the  milk  we  drink,  or  in  the 
intestinal  contents.  Whether  the  intestinal  disturbances 
which  are  common  in  warm  weather  are  due  to  such  bac- 
teria, and  whether  the  summer  troubles  attributed  to  milk 
are  traceable  to  such  organisms,  is  not  known.  It  is  quite 
certain,  however,  that  numerous  putrefactive  bacteria 
present  in  milk  would  render  it  at  least  suspicious.  Milk 
containing  many  such  bacteria  will  be  more  suspicious 
than  milk  with  a  much  larger  number  of  lactic  bacteria. 
If  it  is  possible  by  a  bacteriological  study  of  a  sample  of 
milk  to  detect  the  proportion  of  such  putrefactive  bacte- 
ria, it  will  give  data  which  are  of  significance  in  the  con- 
clusions as  to  the  wholesomeness  of  milk. 

94-  (3)  Bacteria  with  No  Noticeable  Action  on  Milk. 
— These  bacteria  have  apparently  nothing  to  do  with  the 
keeping  properties  of  the  milk,  and  may  be  present  in 
large  numbers  without  producing  any  noticeable  effect. 
Whether  they  are  concerned  in  rendering  the  milk  un- 
healthful  cannot  yet  be  stated.  Probably  some  of  them 
are,  and  if  present  in  considerable  numbers  may  render 
the  milk  unwholesome.  Among  these  the  most  promi- 
nent is  a  variety  of  coccus  forms,  which  belong  to  the  ge- 
nus Streptococcus.  These  are  almost  universally  present 
in  milk.  They  come  in  part  from  the  milk  ducts  (55), 
and  it  is  almost  impossible  to  draw  milk  without  them. 
Their  number  is   sometimes  very  great,  and  sometimes 


152  INFANT   FEEDING. 

small.     Their  significance  in  determining  the  healthful- 
ness  of  milk  cannot  as  yet  be  stated. 

95.  It  is  possible  by  a  simple  modification  of  the 
common  bacteriological  methods  of  analysis  to  study  milk 
in  such  a  way  as  to  differentiate  these  three  types  of  bac- 
teria from  each  other.  While  such  a  differentiation  will 
not,  in  the  present  state  of  our  knowledge,  be  sufficient  to 
determine  accurately  as  to  the  wholesomeness  of  milk,  it 
will  bring  us  much  closer  to  that  end  than  the  method  of 
simply  counting  of  numbers,  and  will  frequently  show 
whether,  in  the  case  of  badly  contaminated  milk,  the 
trouble  is  in  the  improper  conditions  of  the  original  barn 
and  in  uncleanliness  in  milking,  or  due  to  improper  hand- 
ling of  milk  subsequently  to  the  milking. 

96.  If  milk  is  retained  at  a  moderate  temperature  for 
quite  a  number  of  hours,  the  lactic  bacteria  commonly 
grow  rapidly  and  soon  come  to  outnumber  all  the  other 
species  put  together.  In  fresh  milk  it  is  rare  that  the 
lactic  bacteria  are  very  numerous.  Hence  it  follows  that 
if  a  sample  of  market  milk  is  examined  and  found  to  con- 
tain a  large  per  cent  of  lactic  bacteria  of  the  common 
kind,  it  is  due  to  the  fact  that  the  milk  has  been  kept 
moderately  warm  for  a  number  of  hours.  If  the  milk  is 
kept  cool  the  lactic  bacteria  do  not  thus  grow,  and  re- 
main for  a  long  time  in  small  relative  numbers.  The 
presence  of  great  numbers  of  lactic  bacteria,  therefore, 
suggests  insufficient  cooling  of  the  milk  and  perhaps 
greater  age. 

If,  on  the  other  hand,  the  milk  shows  large  numbers  of 
miscellaneous  bacteria,  either  of  the  putrefactive  type  or 
of  those  having  no  effect  on  the  milk,  the  inference  to  be 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     153 

drawn  is  different.  Under  these  conditions  we  are  led  to 
suspect  a  greater  primary  contamination  of  milk  during 
the  milking.  If  there  is  much  filth  in  the  barn  and 
around  the  cow,  the  milk  is  likely  to  be  contaminated 
with  a  large  variety  of  bacteria.  Hence  milk  which 
shows  such  variety  suggests  lack  of  proper  conditions  in 
the  barn.  Thus  the  relative  abundance  of  lactic  and 
other  bacteria  in  a  sample  of  milk  may  give  data  for  con- 
cluding whether  the  milk  was  badly  contaminated  at  the 
start,  or  whether  it  has  simply  been  kept  at  too  high  a 
temperature  so  as  to  stimulate  the  growth  of  lactic  bacte- 
ria. That  there  is  a  practical  advantage  in  such  a  knowl- 
edge will  be  evident  at  once. 

Directions     for     Bacteriological     Examination    of 

Milk. 

97.  In  order  to  make  a  bacteriological  study  of  milk  it 
is  necessary  to  have  a  previous  knowledge  of  ordinary 
methods  of  laboratory  work.  It  is  assumed,  therefore, 
that  those  who  wish  to  use  the  following  method  have  a 
previous  knowledge  of  making  and  using  culture  media, 
and  only  such  points  will  be  explained  in  detail  as  contain 
modifications  of  the  common  laboratory  methods. 

Culture  Medium  No.  1. — Litmus  sugar  gelatin. 

1.    Water 500  c.c. 

Peptone 10  gm. 

Milk  sugar 30     " 

Gelatin 1 20     " 

Liebig's  extract  of  beef 5     " 

These  materials  are  placed  together  in  a  dish  and  dis- 
solved by  heating,  at  a  temperature  below  6o°  C,  to  make 
a  solution  which,  as  will  be  seen,  contains  twice 'the  quan- 


154  INFANT   FEEDING. 

tity  of  the  various  ingredients  that  is  contained  in  the  or- 
dinary gelatin  culture  media.  After  the  material  has  be- 
come thoroughly  dissolved  the  solution  is  neutralized. 
For  neutralization  is  used  a  solution  of  NaOH,  and  the 
neutral  point  is  determined  by  litmus  paper.  A  weak 
solution  of  NaOH  is  added  until  the  material  is  in  the 
very  faintest  degree  alkaline.  In  other  words,  since  the 
solution  is  at  first  acid,  just  enough  NaOH  is  added  to 
pass  the  neutral  point,  as  shown  by  its  action  upon  red 
and  blue  litmus  paper.  After  the  neutralization  the  white 
of  an  egg  is  added  and  the  whole  is  boiled  for  three-quar- 
ters of  an  hour. 

2.   Water 500  c.c. 

Dry  litmus  (in  cubes)    48  gm. 

The  litmus  is  steeped  in  the  water  for  three  hours  or 
more,  at  a  temperature  of  about  6o°  C,  to  dissolve  as 
much  of  the  active  material  as  possible.  The  solution  is 
then  filtered. 

After  solution  i  has  boiled  with  the  white  of  an  egg 
for  three-quarters  of  an  hour,  it  is  mixed  with  the  filtered 
litmus  solution  No.  2,  the  two  together  making  the  bulk 
up  to  about  a  litre,  and  water  is  added  if  necessary  to  re- 
place evaporation.  The  solution  is  then  warmed  slightly, 
though  not  above  6o°,  in  order  to  avoid  as  much  as  possi- 
ble the  changes  in  the  litmus  which  high  temperatures 
produce.  It  is  then  filtered  through  absorbent  cotton, 
distributed  in  sterilized  tubes,  about  8  c.c.  in  each,  and  is 
ready  for  final  sterilization.  The  sterilizing  is  carried  on 
as  usual  by  steaming  on  three  successive  days.  The  ster- 
ilization always  has  a  tendency  to  change  the  color  of  the 
litmus  to  a  reddish  brown,  but  the  blue  is  restored  after 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     155 

the  litmus  cools  and  stands  for  a  few  hours  in  contact 
with,  the  air.  When  finally  sterilized  and  cooled  the  so- 
lution should  be  a  deep  blue  color,  so  deep  a  blue  that 
when  poured  out  in  Petri  dishes  the  color  is  quite  strong. 
The  litmus  of  commerce  is  quite  variable  in  strength, 
three  per  cent  of  litmus  (30  gm.)  being  sometimes  suffi- 
cient to  give  the  required  blue  color,  while  other  lots  of 
litmus  require  40-50  gm.  As  a  rule  48  gm.  to  the  litre 
produces  as  good  a  color  as  can  be  desired,  but  some- 
times, if  the  litmus  is  exceptionally  strong,  a  smaller 
amount  is  preferable.  It  is  advantageous  to  buy  the  dry 
litmus  in  rather  large  quantities,  and  then  after  a  single 
experiment  has  shown  the  amount  of  litmus  of  the  partic- 
ular sample  that  is  needed  to  produce  the  desired  color, 
the  same  percentage  of  litmus  is  employed  until  the 
whole  quantity  of  litmus  has  been  used.  A  new  sample 
of  litmus  will  require  a  new  percentage. 

Culture  Medium  No.  2. — Litmus  Sugar  Agar. — This 
medium  is  prepared  in  exactly  the  same  way  as  was  the 
gelatin  culture  medium,  except  that  one  and  one-half  per 
cent  of  agar  is  added  instead  of  twelve  per  cent  of  gelatin. 
The  other  methods  of  procedure  are  the  same. 

98.  In  the  use  of  these  media  for  the  analysis  of  the 
milk,  the  first  thing  that  is  to  be  done  is  to  determine 
upon  the  proper  dilution  of  the  milk  which  will  give  the 
most  satisfactory  results.  Milk  contains  so  many  bacte- 
ria that  is  never  possible  to  use  as  much  as  1  c.c.  of  milk 
in  a  single  test,  as  is  commonly  done  in  water  testing. 
The  milk  must  therefore  be  diluted  with  sterilized  water. 
The  question  of  determining  the  amount  of  dilution  is 
one  of  the  most  difficult  points  connected  with  the  whole 


1 56  INFANT    FEEDING. 

testing,  from  the  fact  that  different  samples  of  milk  re- 
quire different  dilutions  for  proper  study.  The  dilution 
should  be  such-  that  the  plates  which  are  subsequently 
made  should  contain  from  one  hundred  to  three  hundred 
colonies  of  bacteria.  The  extent  of  the  dilution  of  the 
milk  necessary  to  produce  this  result  varies  with  the  age 
of  the  milk,  with  the  temperature,  and  with  the  season. 
We  have  found  in  winter  weather  that  a  dilution  from 
two  hundred  to  six  hundred  times  is  ordinarily  most  satis- 
factory. In  summer  weather  the  dilution  should  be 
higher.  From  one  thousand  to  five  thousand  dilutions 
are  necessary  if  the  milk  is  somewhat  old  or  during  warm 
weather.  The  determination  of  the  proper  dilution  re- 
quires some  degree  of  judgment  and  experience,  and  it  is 
always  best  to  use  more  than  one  dilution  for  each  experi- 
ment, in  order  that  the  best  results  should  be  obtained. 

Method  of  Procedure. 

99.  Sterilize  a  number  of  small  flasks  which  are 
marked  in  some  way  (best  by  being  etched)  at  the  99  c.c. 
point.  Sterilize  also  a  number  of  small  vials,  some  of 
which  are  marked  at  the  5  c.c.  point,  and  others  at  19  c.c. 
These  vials  should  be  provided  with  corks,  which  are  laid 
loosely  in  the  mouth  during  sterilization,  but  placed  in 
tightly  after  sterilization.  Sterilize  a  litre  or  more  of 
water  in  an  autoclave  under  steam  pressure  in  the  ordi- 
nary manner. 

At  the  beginning  of  an  experiment  fill  one  of  the 
flasks  to  the  99  c.c.  point  with  sterilized  water,  and  fill 
one  of  each  sized  vial  to  its  mark  in  the  same  way.  One 
cubic  centimetre  of  the  milk  is  taken  from  the  milk  to  be 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     157 

tested  in  a  sterilized  1  c.c.  pipette,  and  placed  in  the  flask 
with  the  99  c.c.  of  water;  this  dilutes  it  one  hundred 
times.  One  cubic  centimetre  of  this  mixture  is  then 
placed  in  one  of  the  vials,  in  the  5  c.c.  vial  if  the  dilution 
desired  is  to  be  six  hundred,  and  in  the  19  c.c.  vial  if  the 
dilution  is  to  be  two  thousand. 

Meantime  a  number  of  tubes  of  the  litmus  gelatin  and 
one  or  two  tubes  of  litmus  agar  have  been  melted.  There 
is  now  taken  from  the  flask  containing  the  100  c.c.  milk 
dilution  one-half  of  a  cubic  centimetre  with  a  sterilized 
pipette,  and  this  is  mixed  with  one  of  the  tubes  of  gelatin. 
This,  after  being  thoroughly  mixed  in  the  gelatin  by  a 
gentle  but  thorough  shaking,  is  poured  into  a  Petri  dish 
and  allowed  to  harden.  It  is  best  to  make  at  least  three 
such  inoculations,  each  containing  one-half  of  a  cubic  cen- 
timetre of  the  liquid  in  the  flask.  These  are  then  labelled 
as  diluted  two  hundred  times.  To  obtain  the  dilution  of 
six  hundred  times,  1  c.c.  of  the  mixture  in  the  small  vial 
is  removed  by  a  sterilized  pipette,  and  as  before  mixed 
with  the  gelatin  in  the  gelatin  tubes  and  poured  out  into 
Petri  dishes.  At  least  three  such  plates  should  be  pre- 
pared from  this  dilution,  and  these  must  be  labelled' as 
diluted  six  hundred  times.  If  the  higher  dilution  is  re- 
quired, 1  c.c.  of  milk  from  the  first  flasks  of  100  c.c.  is  to 
be  put  into  the  vial  containing  19  c.c.  of  water.  This 
will  dilute  the  original  milk  two  thousand  times,  and  1  c.c. 
of  this  is  mixed  with  a  tube  of  gelatin  and  poured  out  in 
Petri  dishes  as  usual  and  labelled  as  diluted  two  thousand 
times.  To  obtain  a  dilution  of  four  thousand  times,  one- 
half  a  cubic  centimetre  from  the  vial  is  mixed  with  a  tube 
of  gelatin. 


1 58  INFANT   FEEDING. 

From  each  sample  of  milk  there  should  be  made  at 
least  six  plates,  with  two  different  dilutions.  It  is  desira- 
ble also  to  make  at  the  same  time  two  plates  with  the 
agar  culture  medium,  for  reasons  to  be  mentioned  pres- 
ently. For  this  purpose  i  c.c.  of  the  mixture  diluted  six 
hundred  times  is  placed  in  a  tube  of  agar  culture  medium 
No.  2,  mixed  thoroughly,  and  poured  out  in  a  Petri  dish. 
There  will  thus  be  prepared  for  each  experiment  eight 
plates,  three  of  which  are  made  with  a  dilution  of  two 
hundred  or  two  thousand  in  gelatin,  and  three  in  a  dilu- 
tion of  six  hundred  or  four  thousand  in  gelatin,  and  two 
in  agar.  These  plates  are  then  set  aside  at  ordinary  tem- 
perature to  grow. 

Study  of  Plates. 

ioo.  In  the  study  of  the  plates  it  is  always  necessary 
to  allow  the  plates  to  grow  for  three  or  four  days  if  pos- 
sible. The  reason  for  this  is  that  not  until  the  fourth  day 
do  the  different  colonies  become  so  well  developed  as  to 
be  distinguishable  from  each  other.  The  great  difficulty 
of  the  whole  method  consists  in  the  fact  that  it  sometimes 
happens  that  the  milk  contains  many  liquefying  bacteria 
which  grow  rapidly  and  liquefy  the  gelatin.  If  the  gela- 
tin begins  to  liquefy  rapidly  it  is  necessary  to  study  the 
plates  at  once  in  spite  of  the  fact  that  the  differentiation 
is  not  perfect.  If,  however,  the  liquefying  bacteria  are 
not  numerous  and  do  not  grow  rapidly,  the  plates  may  be 
kept  for  four  or  five  or  even  more  days  before  they  are 
studied.  The  longer  the  plates  grow  the  better  the  dif- 
ferentiation which  is  obtained. 

At  best,  however,  the  presence  of  liquefying  bacteria 


BACTERIOLOGICAL  EXAMINATION  OF  MILK.     159 

will  make  it  impossible  properly  to  differentiate  the  bac- 
teria in  a  considerable  number  of  the  samples  of  milk, 
and  sometimes  they  are  so  numerous  as  to  make  it  even 
impossible  to  determine  the  numbers  of  the  colonies,  to 
say  nothing  of  determining  the  varieties.  For  this  rea- 
son the  two  agar  plates  are  introduced  in  the  experiment; 
the  agar  plates,  not  being  liquefied,  will  serve  as  a  test 
upon  which  we  can  fall  back  if  the  gelatin  plates  become 
ruined  by  the  growth  of  liquefiers.  The  agar  plate  is  not 
so  satisfactory  as  the  gelatin  plate,  and  is  to  be  used  only 
when  the  gelatin  plates  prove  unsatisfactory  because  of 
liquefiers. 

In  the  study  of  the  colonies  on  the  plates,  after  they 
have  satisfactorily  grown,  several  points  are  to  be  deter- 
mined : 

1 .  The  total  number  of  bacteria.  These  are  counted 
by  the  ordinary  methods. 

2.  The  number  of  acid-producing  bacteria.  These 
can  be  easily  detected  from  the  fact  that  each  acid  colony 
will  be  surrounded  by  a  little  red  halo  where  the  acid  col- 
ony has  turned  the  blue  litmus  red.  This  detection  of 
the  acid  bacteria  is  also  possible  on  the  agar. 

3.  The  number  of  liquefying  colonies  is  to  be  counted. 
This  is  especially  important,  inasmuch  as  the  liquefying 
colonies  commonly  represent  the  putrefactive  organisms, 
and  their  relative  abundance  in  milk  is  a  matter  of  impor- 
tance. 

4.  The  number  of  bacteria  producing  no  reaction  in 
the  gelatin  or  an  alkaline  reaction,  and  which  do  not 
liquefy,  is  to  be  counted.  This  is  very  easy  to  do,  pro- 
vided the  plates  have  been   properly  diluted  and  have 


i6o 


INFANT    FEEDING. 


grown  sufficiently.  Where  it  is  necessary  to  study  the 
plates  early  because  of  the  abundance  of  liquefiers,  the 
distinction  between  the  acid  bacteria  and  those  producing 
no  reaction  is  less  sharp  and  not  always  satisfactory. 

The  results  which  are  obtained  should  then  be  tabu- 
lated, and  each  table  should  be  a  double  one.  First, 
there  should  be  given  the  total  number  of  each  type  of 
bacteria  detected;  and  second,  the  percentage  of  each 
type.  The  purpose  of  the  latter  is  to  show  the  relative 
preponderance  of  the  different  micro-organisms.  The 
advantage  of  this  is  considerable.  It  has  been  found  by 
many  experiments  that  usually,  when  milk  becomes  a 
number  of  hours  old,  the  bacteria  increase  rapidly,  but 
the  large  percentage  of  the  numbers  present  are  lactic 
bacteria.  If  the  milk  shows  large  numbers  of  bacteria, 
and  of  this  large  number  the  great  proportion  are  lactic 
organisms,  the  milk  must  be  regarded  as  normal,  though 
rather  old.  If,  on  the  other  hand,  the  results  should  show 
large  numbers  and  a  large  percentage  of  liquefiers,  or  a 
large  percentage  of  the  non-acid  bacteria,  the  milk  must 
be  regarded  as  possibly  more  suspicious.  Examples  of 
the  tests  of  two  samples  of  milk  in  this  manner  will  be 
given  as  follows  in  the  way  of  illustration : 


No.    i. 


Total.        '  Lactic  bacteria. 

Liquefiers. 

Miscellaneous. 

Number  of  bacteria  per  c.  c. 

6,820,000      6,324,000 
i            93 

68,000 
I 

42S,000 
6 

No.    2. 

Number  of  bacteria  per  c.c. 

17,000                500 

5,300 
31 

I  1,200 

66.2 

BACTERIOLOGICAL  EXAMINATION  OF  MILK.     161 

Of  these  two  samples  it  will  be  seen  that  the  first  con- 
tains many  more  bacteria  than  the  second,  but  the  per- 
centage of  lactic  bacteria  is  much  greater.  The  second 
sample  contains  small  numbers,  but  with  a  very  small  per 
cent  of  lactic  bacteria.  The  second  sample  of  milk  is 
doubtless  fresh,  but  the  first  is  a  perfectly  normal  milk 
and  not  suspicious  in  spite  of  its  large  numbers.  If  No. 
i  with  its  high  numbers  had  had  large  percentages  in  the 
third  and  fourth  columns,  it  would  have  been  suspicious. 

This  method  of  testing  milk  is  not  given  here  as  by 
any  means  complete,  nor  is  it  assumed  that  the  results 
obtained  will  enable  us  to  determine  positively  the  whole- 
someness  of  milk.  Such  a  method  of  bacteriological 
study  is,  however,  an  advance  over  the  practice  of  simply 
counting  the  numbers,  which  has  been  the  common 
method  of  the  past. 


CHAPTER  XVI. 


CEREALS   AND   VEGETABLE   FOODS. 


Next  to  milk,  cereals  are  the  most  important  articles 
of  diet,  especially  for  older  infants  and  young  children. 
These  all  contain  more  or  less  fat,  protein,  carbohydrates 
(starch),  and  mineral  matter;   but  these  ingredients  are 

stored  up  in  cells  composed  of 
cellulose.  Cotton  fibre  or  paper 
is  almost  pure  cellulose.  While 
the  herbivorous  animals  can  di- 
gest large  quantities  of  this 
cellulose,  as  their  digestive  tracts 
are  specially  adapted  for  this 
purpose  (6),  human  beings  can- 
not digest  it  except  to  a  very 
limited  extent.  To  enable  the 
human  digestive  juice  to  get  at 
the  nutritious  portions,  vegetable  foods  must  be  cooked, 
which  process  ruptures  the  cells  and  allows  the  digestive 
juices  to  enter  and  dissolve  their  contents. 

101.  The  protein  of  plants  assumes  many  forms,  the 
same  as  in  animal  tissues.  Instead  of  multiplying  the 
weight  of  nitrogen  of  cereals  by  6.25,  as  has  been  usually 
done  in  determining  the  weight  of  protein,  new  factors 
are  being  used,  as  will  appear  farther  on. 


Fig.  35. — Showing  Cells  Containing 
Finely  Divided  Protein  Matter  Inter- 
mingled with  Starch  Grains.  (Good- 
ale.) 


CEREALS  AND  VEGETABLE  FOODS.     163 

The  proteids  of  wheart  flour  (N  X  5.70)  are  composed 
of*: 

Per  cent. 
Albumin,  0.3 — soluble  in  water  ;  coagulable  by  heat. 

Globulin,  .9  "     dilute  salt  solution  ;  coagulable  by  heat. 

Proteose  body,       .2  "     water. 

Gliadin,  6.8  "     dilute  alcohol. 

Glutein,  4.  5 — insoluble  in  water,  salt  solution,  and  dilute  alcohol. 

12.7 

The  proteids  of  barley  (N  X  5.68)  consist  of*: 

(  Leucosin o.  30  per  cent. 

Soluble  proteid.  -j  Hordein 4.00       " 

'  Edestin  proteose 1-95       " 

Insoluble  proteid 4.  50       " 

10.75       " 

Oats  are  said  to  contain  three  principal  forms  of  pro- 
teid, making  a  total  of  about  fourteen  per  cent.  Their 
weight  is  determined  by  N  X  6.10. 

102.  When  most  vegetable  substances  are  boiled  with 
water,  the  heat  and  moisture  combined  cause  the  contents 


Fig.  36.— Wheat  Grain  Showing  Cells  Con- 
taining Starch  Granules.     (Goodale.) 


Fig.  37. — Barley   Grain,    a.  Chaff  ;    fi,  adherent 
cellular  layer  ;  d,  starch  granules.     (Goodale.) 


of  the  cells,  particularly  the  starch  grains,  to  swell  up  and 
break  open  the  cells. 

The  rapidity  with  which  this  process  takes  place  de- 
pends largely  on  the  nature  of  the  substance  to  be  cooked 

*Bull.  13,  Part  9,  Div.  Chemistry,  United  States  Dept.  Agriculture. 


164  INFANT   FEEDING. 

and  its  physical  condition.  Potatoes,  being  very  watery, 
swell  up  and  burst  as  soon  as  the  temperature  reaches 
near  the  boiling  point  of  water. 

Whole  cereals  are  hard  and  dry  and  have  an  outer 
coat  that  is  almost  waterproof,  and  even  when  placed  in 
water  it  is  some  time  before  the  cereals  soften.  If  the 
whole  cereals  are  brought  to  a  boil,  the  starch  in  the 
outer  cells  swell  up  and  the  proteid  coagulates,  thus  form- 
ing a  coating  which  protects  the  interior  of  the  grains 
from  moisture.  It  takes  many  hours  of  boiling  to  disin- 
tegrate such  cereals;  but,  if  the 
cereals  are. first  ground  in  a  mill,  to 
rupture  the  cells,  and  then  boiled  in 
water,  the  swelling  up  and  bursting 
of  the  starch  grains  takes  place  in 
a  few  minutes. 

There    are    a    great    many    so- 
called  "  steam  cooked  "  cereal  break- 
fig.  38. -oat  Grain.  *t,  starch    fast    foods    on    the  market,   which 

granules.     (Goodale.)  j^^     ^^     p^gHy    grOUlld,   that     it 

is  claimed  require  but  a  few  minutes'  cooking,  but  many 
of  them  will  bear  an  hour's  boiling  with  great  advantage 
to  the  user.  When  they  are  thoroughly  cooked,  all  trace 
of  the  original  grain  should  have  disappeared,  or  they 
should  at  least  be  very  soft. 

A  general  idea  of  the  composition  of  such  foods  may 
be  had  from  the  following  analyses  of  some  of  those  best 
known.  It  will  be  noticed  that  there  is  very  little  differ- 
ence between  any  of  them  of  the  same  class.  The  claim 
that  some  of  these  foods  are  equivalent  to  ten  times  their 
weight  of  meat,  wheat,  oats,  or  other  such  food,  should 


CEREALS  AND  VEGETABLE  FOODS. 


165 


not  be  believed,  and  the  use  of  foods  for  which  such  ex- 
travagant claims  are  made  should  be  discouraged.  As  a 
rule,  these  foods  are  very  well  digested  and  absorbed  if 
properly  prepared. 


Corn  Products. 

Pearl  Hominy  * 

Pearl  Samp  * 

Oat  Products. 

Hornby's  steam  cooked  oat- 
meal * 

Quaker  Oats  * 

Wheat  Products. 

Cream  of  Wheat  f 


Germea ' 


Pettijohn's  Breakfast  Food  f 

Pillsbury's  Vitos  f 

Shredded  Whole  Wheat  Bis 
cuit  f 


Wheatena  *. 


Wheatlet  * 

Miscellaneous. 

Cook's  Flaked  Ricef 


Grape  Nuts  f 

Malt  Breakfast  Food  f  . 
Whole  Wheat  Gluten  f. 


Health  Food  Co.'s  Cooked 
Gluten* 

Kingsford  Oswego  Corn 
Starch  * 

Durkee's  Pearl  Tapioca*.  . . 


Proteid. 


I3.05 
H-43 


8.92 
7. 86 


10.2S 

10.70 
9  SO 

10.80 


9-65 

11.78 

11.40 

5-30 

8.00 

11.20 

6.S1 

11.65 
11.46 


N  X  6.25 
8.31 

S.25 
NX  6.31 

16.22 
16.22 

N  X? 
S.io 

NX  5.70 

7.98 

NX? 

11.90 

11. 19 

10.60 

NX  5.70 

12.26 

N  X  5.70 

10.38 

NX? 

7.90 

N  X  ? 

11.70 

NX? 

13.40 

NX? 

15.90 

N  X  6.25 

12.75 
N  X  6.25 

•  44 

•  33 


0.60 

.81 


6.89 
8.23 

.90 


1.88 

1. So 
1.50 

1.50 


3-45 
1. 5i 
1. 00 
1. 10 
2.20 
4.60 

•  7i 
.09 


Carbohydrates 
other  than  fibre. 

—    V 

Ufa 

77.62 

O.63 

79.26 

I.03 

66.16 

I. II 

66.07 

1.25 

Carbohydrates. 

.78.70 

Carbohydrates 
not  fibre. 

78.68 

1. 17 

Carbohydrates. 

73-9° 
76.60 

75.60 

Carbohydrates 
not  fibre. 

73-IO 

1.39 

75-21 

1.0S 

Carbohydrates. 

So.  20 

79.70 

75.00 

65.60 

Carbohydrates 
not  fibre. 

79.96 

.85 

87.48 

•  23 

87.95 

.09 

0.42 

■  25 


1.82 
1.62 

.40 

1. 18 

1.70 
.70 

1.50 
1.54 

1. 12 
O.4O 
2.30 
I.40 
2.70 

I. OI 

••43 
.12 


*  Bull.  No.  13,  Part  9,  Div.  of  Chemistry,  United  States  Dept.  Agriculture, 
f  Bull.  No.  55,  Maine  Agricultural  Experiment  Station. 

Dried  beans  and  peas  are  very  rich  in  protein,  but  as 
usually  cooked,  forty  to  forty-seven  per  cent  of  this  is 


1 66 


INFANT   FEEDING. 


unabsorbed,  and  the  toughness  of  the  cellulose  renders 
them  unsuitable  for  a  steady  diet.  However,  when  made 
into  soup,  beans  and  peas  may  be  used  quite  freely  with 
advantage  after  infancy. 


Composition. 

Water. 

Protein. 

Fat. 

Carbo- 
hydrates. 

Ash. 

Authority. 

IO.4 
9-5 

18. 1 
24.6 

1-5 
I.O 

65-9 
62.O 

4.1 
2.9 

At  water. 

103.  Long  before  children  are  old  enough  to  eat  these 
familiar  foods,  cereals  can  be  and  should  be  used  when 
properly  prepared  and  given  with  discretion.  In  the  sec- 
tion on  "  Practical  Infant  Feeding"  (133)  the  methods  of 
using  cereals  will  be  found,  but  a  rather  detailed  account 
of  the  principles  involved  in  preparing  them  will  be  given 
here. 

Cereals  are  composed  principally  of  stored-up  food  for 
the  plant  germs  which  they  contain.     These  germs  have 


Fig.  39. — Showing  Bursting  of  Starch  Grains  during  Cooking.     (Langworthy.) 

the  power  to  secrete  enzymes  (11),  which  dissolve  nearly 
all  of  this  reserve  food,  that  nourishes  the  little  plant 
until  its  roots  have  obtained  a  hold  in  the  ground  and  its 
leaves  are  above  the  soil.  The  enzymes  produce  for  the 
plant  germ,  as  nearly  as  is  known,  the  same  changes  in 


CEREALS  AND  VEGETABLE  FOODS. 


167 


the  starch  and  protein  of  the  cereals  as  do  the  digestive 
juices  of  human  beings.  These  enzymes,  or  diastases, 
have  different  properties;  some  will  simply  dissolve  the 
cellulose,  others  will  liquefy  the  starches,  and  still  others 
convert  them  into  dextrin  and  maltose.  The  enzymes 
that  dissolve  the  proteids  of  cereals  are  not  of  great  im- 
portance in  preparing  cereals  for  infants. 

By  taking  advantage  of  this  knowledge  (1)  cereals  can 
be  rendered  almost  perfectly  assimilable  by  the  youngest 
infant  with  little  or  no  di- 
gestive effort  on  its  part ; 
(2)  or  the  starch  of  the 
cereal  may  be  simply  ren- 
dered soluble  (137).  This 
is  the  principle  on  which 
Baron  Liebig  prepared  his 
infant  food. 

104.  Another  process 
of  converting  starch  into 
dextrin  and  maltose  con- 
sists of  heating  it  uniform- 
ly to  about  4000  F.  The 
starch  grains  do  not  lose 

their  shape,  but  become  soluble  and  lose  their  chemical 
properties.  An  old  process  of  preparing  wheat  flour  for 
infants  and  invalids  consists  in  placing  several  pounds  of 
flour  in  a  cloth  bag,  and  this  in  a  kettle  of  boiling  water 
and  boiling  for  several  hours.  The  bag  is  then  removed 
and  the  doughy  coating  of  the  mass  removed  and  a  "  flour 
ball  "  remains.  A  much  simpler  method  is  to  put  the  flour 
in  a  "  tin  pudding  bag,"  or  rice  mould,  and  boil  for  an  hour. 


Fig.  40. — Tin  Pudding-Bag  or  Rice  Mould. 


i68 


INFANT   FEEDING. 


The  tube  in  the  centre  of  the  tin  enables  the  flour  to  be- 
come heated  quite  rapidly,  and  if  the  kettle  in  which  the 
boiling  is  done  is  kept  covered  the  temperature  of  the  flour 
will  rise  to  above  200 c  F.,  but  not  quite  to  212°  F.  This 
"baked  flour"  has  a  slightly  yellow  color  and  it  is  often 
said  to  be  " dextrinized,"  or  that  the  starch  in  it  has  been 
converted  into  dextrin.  As  a  matter  of  fact,  none  or  very 
little  of  the  starch  is  converted  into  dextrin,  as  this  process 
does  not  take  place  until  the  heat  is  raised  to  about  4000  F. 
The  change  in  this  "baked  flour"  or  "flour  ball"  lies  in 
the  coagulation  of  tJie  proteids.      If   the  baked  flour   is 

mixed  with  cold  water,  it 
will  not  form  a  dough 
or  even  lumps,  but  will 
settle  out  like  raw  starch. 
When  mixed  with  water 
and  boiled,  there  is  no 
soluble  proteid  to  coag- 
ulate around  the  starch 
grains  and  prevent  their 
swelling  up  and  bursting. 

Fig.  41.— Appearance  of  Starch  Grains  in  Bread  111       this        point        "baked 

from  Flour  Ground  in  Dreef's  Mill;  magnified  no  _  ,,    1  l-     1  l 

diameters  (Reduced  one-third  ;  Bull.  No.  67,  flOUr  haS  2.  Slight  advan- 
U.  S.  D.  A.  Office,  Exper.  Sta.)  .  n  ■,        .    •  . 

tage  over  raw  flour,  but  it 
is  not  so  digestible  as  raw  flour  unless  made  into  gruels, 
as  will  be  explained  in  the  next  paragraph. 

105.  From  the  foregoing  it  might  be  inferred  that 
there  is  no  advantage  in  baking  bread  or  crackers  as  far 
as  change  of  the  starch  goes,  but  this  is  an  error.  When 
flour  is  mixed  with  tepid  water,  there  commences  to  be  a 
conversion  of  starch  into  sugar  that  is  caused  by  enzymes 


CEREALS  AND  VEGETABLE  FOODS. 


169 


natural  to  the  flour,  but  which  are  destroyed  in  the  baking 
process.  During  the  process  of  making  bread  about  six 
per  cent  of  the  starch  is  converted  into  sugar  by  these 
enzymes.  The  object  of  adding  yeast  to  bread  dough  is 
to  cause  the  formation  of  gas,  which,  as  it  expands,  ren- 
ders the  gluten  in  which  the  starch  grains  are  embedded 
porous  and  spongy.  The  heat  of  baking  coagulates  the 
gluten  and  other  coagulable  proteids  and  drives  off  the 


§ 


W     9  ft  «0 


Q  • .-: 


<£W cP-^^u,  • 


»*  '*•    ,° 


5    * 


Fig.  42. — Wheat  Starch  ;  magnified  160  diameters.     (Bull.  No.  13,  Div.  of  Chem.,  U.  S.  D.  A.) 


gas ;  the  result  is  a  porous  food  which  exposes  an  immense 
surface  to  the  digestive  juices.  Few  cereals  contain  as 
much  gluten  as  wheat,  and  consequently  are  not  so  well 
adapted  for  bread-making. 

While  the  starch  of  baked  flour  is  not  in  a  condition 
to  be  easily  digested,  that  of  bread  and  crackers  is  readily 
digested.  There  are  two  reasons  for  this:  (i)  the  action 
of  the  natural  enzymes  of  the  flour  on  the  starch  in  the 
dough  before  baking,  and  (2)  the  effect  of  the  heat  on  the 


170 


INFANT   FEEDING. 


wet  starch  in  the  dough,  which  causes  the  starch  grains 
to  break  open.  The  crust  of  bread  may  contain  a  small 
quantity  of  dextrin  produced  by  heat,  but  none  is  formed 
in  the  interior  of  the  loaf,  as  there  the  temperature  never 
exceeds  2120  F. 

106.  In  selecting  bread  there  is  little  or  no  advantage 
in  choosing  "whole-wheat  bread"  or  Graham  bread  on 
account  of  their  containing  more  mineral  matter  than 
ordinary  bread,  for  digestion  experiments  have  shown 
that  owing  to  the  greater  quantity  of  cellulose  in  these 
breads  absorption  is  not  so  complete  as  with  white  bread. 


Representative 

Analyses  of  Bread.* 

Water. 

Protein. 

Fat. 

Carbohydrates. 

Ash. 

36.06 
41.92 

33.34 

S.7S 
S.24 
9-43 

i-73 
1.05 
2.62 

52.73 
46.85 
48.21 

O.  70 

I.94 

I.40 

Representative  Analyses 

OF    CRA( 

;kers  and  BiscuiTS.f 

Animal  crackers 

Butter  crackers 

Cream  crackers 

Graham  crackers.  .  .  . 

Graham  wafers 

Lunch  milk  biscuits 
Nursery  biscuits.  ... 

Oat  cakes 

Oyster  crackers 

Pilot  biscuits 

Saltines 

Sea  Foam  wafers  .  . 

Soda  crackers 

Water  crackers  .... 
Zwieback 


Water. 


5.42 
9.48 

4.28 
5.24 
3.14 

8.87 

6.72 

7.83 
6.51 

8.18 

6.70 

7-53 
8-43 
6.58 
7-73 


N  X  5.7o 
S.44 

10.21 
9.01 
7-52 
6.79 
8.15 
8.72 

11.97 

10.21 
9-52 

10.21 
9.07 
8.89 

10.83 
9.40 


Ether  ext. 
(Fat.) 


8-37 

3-79 

13-77 

12.04 

10.87 

12.47 

3-54 

S-54 

9.19 

10.  22 

12.68 

10. 17 

7.68 

.21 

9.12 


Crude 
fibre. 


0.4S 

•27 
.80 

•59 
•37 

■  42 

1.86 
.21 
•27 
•34 
•39 

•  25 
•29 

•  30 


Ash. 


Salt. 


O.65 
2.51 
1-33 
1. 18 
I.42 

1. 15 

.62 
2.33 

3-07 

.91 

2.26 

1.44 

2.04 

•49 

•S3 


0.04 

2.25 
•53 
•35 
.29 

•37 
.08 
.05 

2.27 
.40 

1.74 
.98 

1.28 


Carbo- 
hydrates. 


77.12 
69.OI 

7I-56 
74.02 
77.78 
69.36 
80.40 

69-33 
7I.02 
71.17 

68.86 

71-79 
72.96 
81.89 
72.92 


*  Bull.  No.  85,  United  States  Dept.  of  Agric. ,  office  of  Exper.  Stations. 
±  Bull.  No.  13,  Part  9,  United  States  Dept.  Agric,  Div.  of  Chemistry. 


CHAPTER  XVII. 
PROPRIETARY    INFANT    FOODS. 

These  foods  are  largely  made  from  wheat  flour,  to 
which  may  have  been  added  a  small  quantity  of  milk, 
beef  extract,  or  sugar. 

In  the  foods  that  are  to  be  dissolved  in  water  the 
starch  has  been  converted  into  dextrin  and  maltose  by 
the  action  of  diastase,  the  starch-digesting  enzyme  of 
plants  (103);  and  in  the  foods  that  are  to  be  cooked,  the 
flour  has  been  baked,  as  can  be  done  at  home  by  the  use 
of  the  "tin  pudding  bag"  (104),  hence  the  principles  used 
in  theii  manufacture  are  the  same  as  those  explained  in  the 
previous  chapter. 

From  a  nutritional  standpoint  these  foods  by  them- 
selves are  almost  without  exception  inferior  to  the  best 
grades  of  condensed  milk.  When  used  with  cow's  milk, 
however,  many  of  them  are  effective  diluents,  especially 
those  containing  baked  flour.  Incases  of  indigestion  they 
sometimes  prove  helpful,  but  as  a  steady  diet  for  an  in- 
fant they  should  not  be  used  unless  along  with  a  liberal 
amount  of  fresh  milk. 

Analyses  of  those  foods  that  are  said  to  have  the  larg- 
est sale  are  here  given,  with  analyses  of  condensed  whole 
and  skim  milk,  and  wheat  flour.  It  will  be  noticed  that 
many  of  the  foods  contain  not  much  more  fat  than  con- 
densed skim  milk.     Fat  is  a  very  important  food  element 


172 


INFANT   FEEDING 


when  derived  from  milk,  as  it  then  contains  lecithin,  one 
of  the  nerve-building  elements.  Whenever  it  is  possible, 
an  infant  should  have  a  sufficient  quantity  of  fat  from 
fresh  milk. 


Moist- 
ure. 

Fat. 

Pro- 
teids. 

Carbo- 
hydrates. 

Ash. 

Crude 
fibre. 

Condensed  whole  milk  (sweetened)  * 

24.06 
29.23 

12.28 

"11.28 

.64 
Ether 
ext. 
I.30 

9-36 
to.  73 

10.18 

52. 2S 
55-69 

75-63 

2.13 
2.63 

.61 

O.28 

Proprietary  Infant  Foods  which  have  Principal 
Sale  in  New  York. 


Class  I.  To  be  used  with  water;  no  cooking  re- 
quired. 

Allenbury's  Foods  Nos.  1  and  2.  Cereal  Milk,  Malted 
Milk,  Milkine.  These  foods  are  said  to  be  prepared  by 
mixing  a  certain  amount  of  sugar,  or  dextrin  and  maltose, 
derived  from  the  starch  of  wheat  flour  with  milk  and  dry- 
ing. 

Analyses  to  represent  this  class  \% 


Allenbury's  Food  No.  I  §  . 
Allenbury's  Food  No.  2  §  . 


Malted  Milk 


Moist- 
ure. 

Fat. 

5-7 

I4.OO 

3-9 

12.30 

2-55 

I. 41 

Proteids. 


Soluble 
carbo- 
hydrates. 


NX  5-7 

9  7 

9.2 

N  X  6.25 

14.00 


66.85 
72.10 

63.87 


Insoluble 

carbo- 
hydrates. 


15.68 


3-75 
3-50 


1-57 


*  Richmond's  "  Dairy  Chemistry." 

f  Bull.  13,  Part  9,  Div.  of  Chemistry,  U.  S.  Department  Agriculture. 

%  See  first  note  on  page  173. 

^  Hutchinson  :   "  Food  and  the  Principles  of  Dietetics." 

U  Bull.  59,  Laboratory  of  the  Inland  Revenue  Department,  Canada. 


PROPRIETARY   INFANT   FOODS.  173 

Class  II.  To  be  used  with  water;  cooking  required. 
These  foods  are  said  to  be  prepared  by  adding  to  some 
dried  milk,  sugar,  and  baked  wheat  flour.  The  cooking 
with  water  is  to  rupture  the  starch  grains. 

Analysis  to  represent  this  class*: 

Nestle' s  Milk  FooD.f 


Moisture 2. 18 

Fat 4.45 

Proteids 10.72 


Soluble  carbohydrates 43. 84 

Insoluble           "          (starch)  35.34 
Ash 1.60 


Class  III.  To  be  used  with  milk;  no  cooking  re- 
quired. 

These  foods  are  said  to  be  made  from  wheat  flour  by 
converting  the  starch  into  dextrin  and  maltose  by  dias- 
tatic  action  (103). 

.Analysis  to  represent  this  class:* 

Mellin's  Food,  f 


Moisture 4.  72 

Fat 30 

Proteids,  N  X-  6. 25 10. 10 


Soluble  carbohydrates 82. 06 

Insoluble  carbohydrates 

Ash 3.  50 


This  food  often  gives  good  results  by  acting  as  an 
effective  attenuant  of  the  curd  of  cow's  milk  to  which  it  is 
added. 

Class  IV.  To  be  used  with  milk;  cooking  required. 

Carnrick's  Soluble  Food,  Eskay's  Food,  Health  Food 
Company's  Barley,  Hubbel's  Prepared  Wheat,  Imperial 
Granum,  Ridge's  Food,  Robinson's  Patent  Barley.  With 
the  exception  of  Carnrick's  Food  these  are  said  to  be 
principally  made  up  of  baked  wheat  or  barley  flours. 

*  It  is  impossible  to  give  the  composition  of  the  food  as  it  will  be  in  the  in- 
fant's feeding  bottle,  as  this  will  depend  on  the  dilution  of  the  food  and  the  quan- 
tity of  milk    that  is  added  to  it. 

f  Bull.  59,  Laboratory  of  the  Inland  Revenue  Department,  Canada. 


i74  INFANT   FEEDING. 

Analyses  to  represent  this  class* : 


Carnrick's  soluble  food  f  .  — 

Imperial  Granum  f 

Ridge's  Food  f 

Health  Food  Co.'s  Barley  %. . 
Robinson's  Patent  Barley  f  .  . 


Soluble 

Insoluble 

Moist- 

Fat.    i    Proteids. 

carbo- 

carbo- 

Ash. 

ure. 

hydrates. 

hydrates. 

NX  6.25 

5.69 

2.1S 

16.60 

N  X  6.25 

33.21 

34-54 

2.73 

6.04 

.72 

13-77 
N  X  6.2^ 

3-94 

67.46 

•49 

S.I2 

.43 

13-83 

NX  5-82 

5.02 

69.24 

•53 

IO.92 

.S9         6.9S 

|nx  6.25 

7 

So.  3  5 

.36 

9.41 

•  41 

7.46 

2.91 

7S.66 

•94 

These  foods  often  form  effective,  though  expensive, 
diluents  of  ordinary  cow's  milk. 

*  See  first  note  on  page  173. 

f  Bull.  59,  Laboratory  of  the  Inland  Revenue  Department,  Canada. 

%  Bull.  13,  Tart  9,  Div.  of  Chemistry,  U.  S.  Department  Agriculture. 


CHAPTER   XVIII. 
MEATS   AND    EGGS. 

Scraped  Beef — Beef  Juice— Beef  Extracts  and  Teas 
— Meat  Broths  and  Soups — Eggs. 

107.  Meats  play  but  a  small  part  in  infant  feeding,  yet 
there  is  a  great  deal  of  misapprehension  as  to  their  value. 

It  is  impossible  to  give  the  composition  of  meat,  as  it 
varies  greatly  with  the  cut.  However,  in  a  general  way  it 
consists  of : 

Water 50  to  75  per  cent. 

Protein 1 5  to  20        " 

Fat 1 5  to  20 

Mineral  matter 1  to    3        " 

The  protein  or  proteid  of  meat  is  a  mixture  of  several 
protein  bodies,  some  soluble  in  water  and  salt  solution 
and  coagulable  by  heat  (albumins  and  globulins),  and  oth- 
ers insoluble.  A  detailed  account  of  these  proteids  will 
be  found  in  Chapter  III.  About  the  only  attempt  to 
separate  the  proteids  of  meat  in  infant  feeding  is  in 
preparing  scraped  beef,  or  beef  pulp,  and  beef  juice. 
Meat  broths  and  soups  contain  the  extractives  of  the 
meat,  but  only  a  small  quantity  of  proteid.  These  prep- 
arations are  all  useful  in  cases  of  poor  digestion,  as  will  be 
explained  presently. 

108.  Scraped  Beef  or  Beef  Ptilp. — If  a  piece  of  lean 


i;6  INFANT   FEEDING. 

beef  is  scraped  with  a  spoon,  a  finely  divided  pulpy  mass 
will  be  obtained  on  the  spoon  and  a  stringy  fibrous  mass 
will  remain,  which  consists  of  the  connective  material  of 
the  meat.  Upon  boiling,  this  fibrous  matter  is  converted 
largely  into  gelatin,  which  gives  the  "body"  to  beef 
soups. 

The  gastric  juice  has  a  particular  solvent  action  on  the 
fibrous  matter  of  meat,  and  causes  the  meat  in  the  stom- 
ach to  swell  up  and  disintegrate  into  a  pulpy  jelly,  which 
can  easily  pass  into  the  intestine  where  the  principal  chem- 
ical changes  take  place  during  digestion.  As  the  intesti- 
nal juices  do  not  cause  meat  to  swell  up  and  disintegrate, 
but  attack  the  meat  only  on  the  outside  surface,  digestion 
is  very  slow  in  the  intestine  unless  the  gastric  juice  has 
first  done  its  preparatory  work  (n,  151). 

In  infants  the  stomach  is  not  fully  developed  and 
consequently  for  them  meats  are  very  indigestible.  How- 
ever, if  the  meat  pulp  is  removed  from  the  connective 
material,  older  infants  can  take  care  of  it  without  difficulty, 
as  it  can  easily  pass  into  the  intestine  where  the  chemical 
processes  have  been  established.  Scraped  beef  has  a 
highly  nutritive  value. 

109.  Beef  Juice. — By  pressure  a  certain  amount  of 
juice  can  be  obtained  from  lean  beef,  especially  if  the 
meat  has  been  slightly  broiled,  which  causes  it  to  con- 
tract greatly.  This  juice  is  not  blood,  but  muscle  serum. 
Its  solids  consist  principally  of  fat,  albumins,  and  globu- 
lins, which  coagulate  upon  heating,  certain  by-products 
of  proteid  metabolism,  called  extractives  or  meat  bases, 
and  salts. 

The  proteids  of  this  beef  juice  or  muscle  serum  are 


MEATS   AND   EQGS.  177 

not  the  same  as  those  of  the  muscle  plasma  that  exists  in 
the  living  muscle.  Shortly  after  an  animal  is  killed  its 
muscles  become  hard  and  stiff.  This  is  caused  by  a  coag- 
ulation of  the  muscle  plasma;  during  this  process  the 
coagulable  proteids  are  separated  from  the  non-coagulable 
ones,  which  can  then  be  expressed  with  the  juice  by  press- 
ure. This  process  of  separation  of  proteids  is  well  illus- 
trated in  the  clotting  of  blood.  It  will  be  seen,  then,  that 
beef  juice  does  not  represent  all  the  proteids  of  meat,  but 
only  a  portion  of  them. 

Another  process  of  preparing  beef  juice  consists  of 
cutting  the  meat  into  small  pieces  and  pouring  over  it 
cold  water,  which  dissolves  out  some  of  the  soluble  mat- 
ter, and  then  pressing.  Such  juice  is  poorer  in  solids 
than  the  expressed  juice. 

Expressed  beef  juice  contains,  according  to  different 
authorities,  quoted  by  Hutchinson,  from  two  per  cent  to 
seven  per  cent  of  proteid  coagulable  by  heat. 

As  a  nutrient  beef  juice  is  not  of  great  value,  because 
not  enough  can  be  given  to  furnish  sufficient  nourish- 
ment, as  it  has  a  tendency  to  cause  looseness  of  the  bow- 
els. It  has,  however,  a  great  value  as  a  digestive  stimu- 
lant when  given  with  other  foods,  as  the  extractives  and 
salts  it  contains  have  a  powerful  effect  in  stimulating  the 
appetite  and  flow  of  digestive  juices.  The  red  color  of 
meat  is  caused  by  oxyhemoglobin,  and  as  some  of  this 
passes  into  the  meat  juice  it  has  a  certain  value  in  fur- 
nishing iron  in  addition  to  its  nutritional  and  stimulating 
properties  (152). 

no.    Meat   Extracts. — If    lean   beef,  cut   into    small 

squares,  is  placed  in  cold  water,  a  large  part  of  the  albu- 
12 


1 78  INFANT   FEEDING. 

mins,  globulins,  extractives,  and  salts  will  dissolve.  If  the 
meat  is  expressed  and  removed,  a  diluted  beef  juice  re- 
mains. Boiling  this  juice  coagulates  the  albumins  and 
globulins.  When  the  coagulated  matter  is  removed,  a 
clear  beef  tea  or  soup  remains  which  contains  the  extrac- 
tives and  salts  of  the  meat  that  give  it  flavor,  but  little  or 
none  of  its  nutritive  elements.  When  this  clear  tea  or 
soup  is  evaporated  to  a  semi-solid  consistency,  the  product 
is  called  extract  of  beef .  It  has  all  the  favor  of  the  beef, 
while  the  meat  from  which  it  was  made  is  almost  taste- 
less. In  making  meat  extracts,  beef  is  used  in  preference 
to  other  meats  because  it  contains  a  larger  proportion  of 
extractives  and  salts. 

Many  believe  that  the  strength  and  value  of  meat  lie 
in  these  extracts  and  that  the  meat  from  which  they  are 
made  is  worthless;  but  this  is  not  the  case.  At  the  close 
of  the  Spanish-American  war  there  was  an  investigation 
into  the  process  of  preparing  the  so-called  canned  roast 
befef  that  was  furnished  to  the  American  soldiers  and 
sailors,  owing  to  the  charges  that  it  was  tasteless  stuff 
made  of  extracted  meat  and  therefore  worthless.  This 
meat  was  first  parboiled  to  cause  it  to  shrink  and  thus 
drive  off  much  of  the  water  it  contained;  it  was  then 
placed  in  cans  and  cooked  again  and  the  cans  were  sealed. 
In  the  course  of  this  investigation  large  quantities  of  meat 
were  put  through  the  process  of  canning  before  the  court 
of  inquiry,  and  samples  were  taken  at  each  stage  of  the 
process  and  analyzed.  A  single  illustration  will  suffice  to 
show  what  changes  took  place  in  the  cooking  process  and 
the  quantity  of  nutriment  extracted.  The  meat  was 
placed  in  water  at  500   F.  and  steam  injected.     In  five 


MEATS   AND    EGGS. 


179 


minutes  the  temperature  reached  1220  F.,  and  in  eleven 
minutes  reached  the  boiling  point.  The  meat  was  then 
boiled  for  one  hour. 

598  Pounds  of  Fresh  Beef  Boiled  One  Hour. 

Extracted  by  Boiling. 

Pounds. 

Water 243.2 

f  Coagulated 

Globulins 


Composition  of  Beef. 

Pounds. 

Water  414. 6 

f  Coagulated 75-9 

I  Globulins 18.3 

Proteids  -\   Proteose    \ 

I   Peptones   I-  . . , 6.3 

L  Gelatin       ) 

Meat  bases 6.  7 

Fat 63.9 

Ash 6. 8* 

Undetermined 5.5 


Proteids  *J  Proteose    \ 

1  Peptones    - 1.3 

(^  Gelatin      ) 

Meat  bases 3.4 

Fat 39.2 

Ash 4. 2f 

Undetermined 


In  this  test  the  shrinkage  amounted  to  4649  per  cent 
of  the  fresh  meat.  Practically  no  proteids  were  ex- 
tracted. 

From  this  598  pounds  of  beef  1,500  pounds  of  "soup 
liquor"  were  obtained,  which  had  the  following  compo- 
sition: 

Solids 0. 92  per  cent. 

Proteids 09       " 

Meat  bases 23        " 

Ash 2S 

Sodium  chloride 11        " 

This  soup  liquor  when  evaporated  down  is  used  in  the 
manufacture  of  beef  extract.  It  is  easy  to  see  that  the 
extract  of  beef  will  have  little  or  no  nutritive  value,  but 
the  claims  of  the  manufacturers  that  one  pound  of  beef 
extract  represents  one  hundred  pounds  of  beef  is  not 
far  from  correct.  Boiled  meat  may  be  tasteless,  but  its 
nutritive  value  is  not  diminished  to  any  extent. 

in.  Meat  Broths. — If  finely  divided  meat  and  cracked 

*  Sodium  chloride,  1.5  pounds.  f  Sodium  chloride,  1.6  pounds. 


1 80  INFANT   FEEDING. 

bones  are  boiled  for  a  long  time  the  connective  material 
of  the  meat  and  the  cartilaginous  materials  of  the  bones 
are  converted  into  gelatin,  which  is  soluble  in  hot  water. 
Broths  so  made  usually  gelatinize  on  cooling.  They  con- 
tain the  salts  and  extractives  of  the  meat  in  addition  to 
the  gelatin.  If  the  meat  which  is  disintegrated  is  not 
strained  off,  the  nutritive  value  of  the  broth  will  be  in- 
creased just  so  much.  In  preparing  broths  the  bones  of 
young  or  small  animals  which  are  not  so  ossified  as  those 
of  older  animals  yield  best  results.  Hence  the  wide  use  of 
chicken,  veal,  and  mutton  for  this  purpose.  These  broths 
have  a  useful  place  in  infant  dietetics  when  milk  must 
be  withheld,  especially  when  prepared  with  cereals  (154). 

112.  Beef  Preparations. — Within  the  past  few  years 
there  has  been  an  increasing  number  of  beef  preparations 
on  the  market.     These  maybe  divided  into  three  classes: 

I.  Beef  extracts  prepared  from  "soup  liquor"  or  other 
meat  as  just  described.  These  should  be  looked  upon  as 
flavoring  agents. 

II.  Beef  juice  prepared  by  expressing  meat  as  previ- 
ously described  (109).  These  have  about  the  same  value 
as  home-expressed  beef  juice. 

III.  Predigested  beef,  which  is  composed  of  albumoses 
and  peptones  produced  by  the  articial  digestion  of  beef. 

As  meats  play  so  small  a  part  in  infant  feeding,  these 
preparations  have  not  a  wide  use  and  will  not  be  de- 
scribed. 

Eggs. 

113.  It  is  a  remarkable  coincidence  that  eggs  are  as 
highly  specialized  in  their  composition  as  it  has  been 
shown  that  milks  are  (6,  31). 


MEATS   AND    EGGS.  181 

Eggs  are  divided  into  two  great  classes. 

I.  Those  from  which  the  young  birds  emerge  devel- 
oped sufficiently  to  move  about  and  feed  themselves. 
Example,  hen's  eggs. 

II.  Those  from  which  the  young  birds  emerge  in  a 
helpless  condition  and  need  further  development  before 
being  able  to  move  about  and  feed  themselves.  Exam- 
ple, robin's  and  sparrow's  eggs. 

There  are  wide  differences  in  composition  between 
these  two  types  of  eggs. 

Hen's  eggs  have  a  useful  place  in  feeding  infants  and 
young  children,  as  they  contain  large  quantities  of  cell- 
building  materials  (2,  3). 

The  weight  of  eggs,  according  to  Hammarsten,  varies 
between  40  and  60  gms. 

The  yolk  weighs  12  to  18  gm.  and  contains,  accord- 
ing to  Parkes,  quoted  by  Hammarsten: 

Water 47 . 1 9  per  cent. 

Proteids ■ 1 5 .  63 

Fat 22. 84 

Lecithin 10. 72 

Cholesterin 1.75 

Salts  insoluble 3-53 

Salts  soluble 6. 12 

The  white  weighs  23  to  34  gms.,  and  contains,  ac- 
cording to  Hammarsten : 

Water 85  to  SS  per  cent. 

t  Ovalbumin     \ 
Proteid  X  Ovaglobulin   > 10  to  13        " 

'  Ovamucoid     / 

Salts 0.7  " 

Fats  "1 

Soaps 

T      ....  V Trace. 

Lecithin 

Cholesterin 


1 82  INFANT    FEEDING. 

There  are  many  subdivisions  of  these  ingredients  of 
both  the  yolk  and  white  of  eggs  that  are  not  of  interest 
here.  It  will  be  noticed  that  there  is  an  absence  of  carbo- 
hydrates in  eggs.  The  function  of  carbohydrates  in  food 
is  to  furnish  heat.  As  the  mother  bird  sits  on  the  eggs 
and  keeps  them  warm  during  incubation,  the  developing 
chick  has  little  need  for  heat-producing  food,  and  it  is  not 
found  in  eggs.  Whole  eggs  may  be  looked  upon  as  a 
tissue-building  food,  but  not  as  a  complete  food;  for  in- 
fants or  adults  need  in  addition  liberal  quantities  of  carbo- 
hydrates. 

White  of  egg  should  not  be  used  as  the  sole  source  or 
main  source»of  proteid  for  infants,  as  it  cannot  build  up 
cells.  Experiments  in  feeding  animals  with  white  of  egg 
have  shown  it  not  able  to  support  life.  In  certain 
forms  of  indigestion  it  may  be  used  temporarily  with 
benefit. 

Flavor  of  Eggs. — The  flavor  of  eggs  may  be  the  result 
of  two  causes:  i.  From  the  hens  eating  highly  flavored 
or  animal  food.  2.  From  changes  that  take  place  in 
eggs  that  are  kept  for  any  length  of  time,  probably  due 
to  bacterial  infection. 

Mai'ket  Eggs. — Eggs  for  the  New  York  market,  and 
probably  for  other  large  cities,  come  from  a  wide  area  of 
country  and  are  divided  into  four  grades. 

First  Grade,  or  Hennery  Eggs.  These  are  from  se- 
lected breeds  of  fowls  and  are  from  three  to  five  days  old 
when  sold. 

Only  a  few  high-grade  stores  have  these,  and  they 
bring  from  ten  to  fifteen  cents  a  dozen  above  the  price  of 
the  next  grade. 


MEATS   AND    EGGS.  183 

Second  Grade,  or  New  Jersey,  New  York,  and  Penn- 
sylvania State  Eggs,  which  are  about  a  week  old  when 
they  arrive  in  New  York.  These  are  what  would  be  gen- 
erally called  first-class  eggs  and  are  kept  by  the  best 
stores. 

Third  Grade,  or  Packing  Eggs.  These  are  from  Illi- 
nois, Indiana,  Iowa,  Michigan,  and  Ohio,  and  are  at  least 
two  weeks  old  when  they  arrive  in  New  York.  These 
are  the  eggs  found  in  the  general  run  of  stores. 

Fourth  Grade,  or  Kentucky,  Missouri,  and  Tennessee 
Eggs.  The  hens  that  produce  these  eggs  are  not  care- 
fully fed,  being  allowed  to  run  at  large  and  eat  anything 
they  can  find,  consequently  the  eggs  are  strong  in  flavor 
and  watery  and  spoil  easily.  These  are  the  cheapest 
eggs  that  are  sold. 

Preservation  of  Eggs. — As  the  shells  of  eggs  are  por- 
ous, bacteria  find  their  way  into  eggs  and  set  up  putrefac- 
tive changes  which  soon  spoil  them.  If  the  egg  lies  on 
one  side  too  long  the  yolk  will  move  to  that  side  and  stick 
to  the  shell.  To  preserve  eggs  from  these  changes  they 
are  often  kept  cool  or  immersed  in  a  solution  of  silicate 
of  soda  (water  glass)  or  lime  water,  which  fills  up  the 
pores.  Eggs  kept  in  silicate  of  soda  solution  have  been 
kept  three  and  one-half  months  without  apparent  change 
in  flavor  or  in  position  of  the  yolk.  "When  such  eggs  are 
boiled,  they  are  apt  to  burst  open  as  the  steam  generated 
inside  the  shell  cannot  escape  through  the  closed  pores. 
To  overcome  this  objection  egg  dealers  prick  the 
shell. 

Candled  Eggs. — A  perfectly  fresh  egg,  when  held  be- 
fore a  candle  in  a  dark  room,  appears  almost  translucent. 


i84  INFANT   FEEDING. 

Cloudiness  denotes  a  change  in  the  egg;  when  decayed 
or  rotten,  it  appears  very  dark  or  black.  This  is  a  very 
simple  way  of  selecting  fresh  eggs.  An  absolutely  fresh 
egg  should  be  obtained  in  order  to  get  a  clear  idea  of  how 
it  appears. 


PART    III. 


CHAPTER    XIX. 

BREAST  FEEDING  — DIET  AND  CARE  OF 
MOTHER  — ELIMINATION  OF  DRUGS  IN 
MILK— CARE  OF  NIPPLES— CONTRAINDICA- 
TIONS—MENSTRUATION— P  REGNANCY— 
WET-NURSING  — WEANING  AND  MIXED 
FEEDING. 

114.  When  it  is  possible  for  the  mother  to  nurse  her 
offspring,  comparatively  little  difficulty  will  usually  be 
experienced  in  properly  nourishing  the  infant.  In  view 
of  this  fact  all  possible  foresight  should  be  used  in  fitting 
the  prospective  mother  for  her  duties. 

For  several  months  before  expected  delivery,  the  nip- 
ples should  be  gently  rubbed  between  the  thumb  and  fin- 
gers, depressed  or  misshapen  nipples  being  thereby  drawn 
out  and  developed ;  this  also  toughens  them  and  prevents 
possible  tenderness  or  fissure  that  would  interfere  with 
nursing.  Tight  clothing  over  the  breasts  should  be 
avoided.  Bathing  the  nipples  with  boric  acid  or  borax 
solution,  one-half  teaspoonful  to  a  cup  of  water,  promotes 
cleanliness  and  thereby  tends  to  avoid  possible  infection 
and  soreness  during  the  nursing  period. 

After  the  mother  is  sufficiently  rested  from  the  labor 
the  baby  should  be  put  to  each  nipple.  If  this  does  not 
satisfy,  and  the  infant  becomes  fretful  or  restless,  a  tea- 
spoonful  or  so  of  boiled  water  may  be  given.  This  not 
only  quiets  the  infant,  but  helps  to  wash  out  the  digestive 


1 88  INFANT   FEEDING 

tract  and  kidneys.  For  the  first  day  or  two  the  infant 
may  be  put  to  the  breast  at  three-hour  intervals  during 
the  day  and  at  four-  to  six-hour  intervals  at  night ;  after 
this  every  two  hours  during  the  day  and  once  or  twice  at 
night.  The  infant  should  not  be  allowed  to  occupy  the 
bed  of  the  mother  at  night,  as  this  is  a  common  cause  of 
too  frequent  nursing.  Regularity  of  feeding  is  essential, 
us  tlie  composition  of  milk  varies  zvith  unequal  intervals 
between  nursings.  The  shorter  the  intervals,  the  richer 
the  milk  is  in  fat,  so  it  is  well  each  day  to  write  down  the 
hours  at  which  nursings  are  to  be  given,  as  5,  7,  9,  11  a.m., 
*>  3»  5»  7>  9  p-M->  etc-  When  the  amount  of  milk  is  suffi- 
cient, the  baby  will  suckle  for  fifteen  or  twenty  minutes 
and  then  drop  off  contentedly  to  sleep.  If,  on  the  con- 
trary, the  baby  tugs  at  the  nipple  for  twenty-five  or  thirty 
minutes,  and  then  frets  after  leaving  it,  there  has  not  been 
sufficient  milk  secreted. 

115.  In  cases  in  which  the  milk  flow  is  scanty  or  does 
not  agree  with  the  infant,  particular  attention  should  be 
paid  to  the  diet  and  hygiene  of  the  mother.  Southworth, 
who  has  made  a  special  study  of  this  subject,  states  that 
much  more  than  is  generally  believed  can  be  accomplished 
in  this  direction.  Nursing  is  a  purely  animal  function 
and  a  great  deal  can  be  learned  from  the  study  of  the 
secretion  of  milk  by  cows.  Here  it  has  been  found  that 
secreting  milk  is  hard  zvork,  and  that  a  cow  in  milk  needs 
as  much  food  as  an  ox  doing  heavy  work.  The  best  cow 
is  one  whose  digestive  and  excretory  systems  are  highly 
developed  and  who  has  no  tendency  to  lay  on  fat.  Such 
a  cow  is  virtually  a  milk  manufactory. 

Therefore  it  is  useless  to  expect  any  mother  to  supply 


BREAST   FEEDING.  189 

thirty  to  forty  ounces  of  milk  daily,  containing  about  five 
ounces  of  solids,  the  proteid  of  which  is  equivalent  to 
about  a  quarter  of  a  pound  of  meat,  unless  she  eats  and 
digests  a  liberal  quantity  of  food. 

The  diet  of  the  mother  should  consist  of  plenty  of 
plain,  easily  digested  food,  meat,  milk,  eggs,  and  well- 
cooked  cereals  (102)  predominating.  Tea  and  coffee 
should  be  withheld,  as  they  have  a  tendency  to  diminish 
the  feeling  of  hunger  and  thus  cause  less  food  to  be  eaten 
and  digested,  while  cocoa  and  chocolate  may  be  drunk 
in  moderation.  Liquid  malt  extracts  may  have  a  benefi- 
cial effect  by  toning  up  the  digestive  system,  thereby  en- 
abling more  food  to  be  digested,  but  not  by  any  particular 
property  of  making  milk.  Southworth  recommends  to 
have  the  mother  drink  between  meals  a  bowlful  at  a  time 
of  a  well-cooked  and  salted  gruel  made  from  yellow  corn- 
meal.  This  not  only  contains  nourishment  and  water 
that  is  needed,  but  undoubtedly  has  by  its  coarse  particles 
a  beneficial  effect  in  increasing  the  amount  of  faecal  mat- 
ter (27)  and  thus  keeping  the  bowels  regular. 

116.  It  is  well  known  that  volatile  substances  in  food 
readily  find  their  way  into  milk  and  that  the  flavor  of  a 
cow's  milk  is  often  affected  by  her  food ;  also  that  under 
certain  conditions  urea  is  found  in  appreciable  quantities 
in  milk.  For  these  reasons  highly  flavored  food  should 
be  avoided  and  strict  attention  should  be  paid  to  the 
excretory  organs,  so  that  products  shall  not  be  thrown  off 
with  the  milk  which  should  pass  off  in  the  urine. 

Constipation  in  the  mother  should  be  overcome  by 
the  use  of  drugs  if  copious  quantities  of  the  cornmeal 
gruel  do  not  relieve  this  condition.     In  selecting  drugs 


190  INFANT   FEEDING. 

for  this  purpose,  those  whose  principal  action  is  on  the 
muscular  coat  of  the  bowel,  rather  than  on  the  glandular 
apparatus,  should  be  chosen.  Cascara  is  one  of  the  best 
for  this  purpose.  Anaemia  should  be  overcome  by  gen- 
erous diet  and  the  exhibition  of  iron. 

Great  care  must  be  exercised  in  the  administration  of 
drugs  to  nursing  women,  as  they  may  be  excreted  in  the 
milk.  Thus  morphine,  mercury,  quinine,  iodide  of  pot- 
ash, and  similar  preparations,  may  have  a  marked  effect. 
This  is  especially  apt  to  happen  when  the  mother  is  in  a 
disturbed  condition,  and  consequently  the  excretory  or- 
gans and  mammary  glands  are  not  in  a  normal  state  of 
equilibrium. 

117.  The  great  and  sudden  variations  in  composition 
of  milk  are  the  result  of  nervous  influences,  and  as  diges- 
tion is  also  greatly  affected  by  anxiety,  fright,  fear,  or 
other  nervous  disturbances,  particular  attention  should  be 
paid  to  keeping  the  mother  in  a  cheerful  state  of  mind 
and  to  seeing  that  her  rest  at  night  is  not  too  much  broken. 
As  fresh  air  is  very  invigorating,  a  walk  that  stops  short 
of  fatigue  or  a  drive  with  pleasant  company  will  have  a 
beneficial  effect. 

118.  In  cases  in  which  the  mother  or  nurse  is  robust 
and  has  a  plentiful  supply  of  milk  that  disagrees  with  the 
infant,  it  may  prove  advantageous  to  cut  down  the  diet, 
particularly  of  proteids  (meat,  eggs,  etc.),  as  they  have  a 
tendency  to  increase  the  percentage  of  fat  and  proteids 
in  the  milk.  With  the  reduction  of  diet  should  go  an 
increase  of  exercise,  causing  to  be  used  up  some  of  the 
excess  of  food  eaten,  and  possibly  the  exhibition  of  sa- 
line cathartics. 


BREAST    FEEDING.  191 

If,  with  the  means  indicated,  it  is  impossible  to  keep 
the  infant  steadily  gaining  in  weight,  four  to  six  ounces  a 
week,  with  good  digestion  and  normal  stools  (156),  one  or 
two  artificial  feedings,  alternating  with  breast  feedings 
when  possible,  should  be  given  daily,  as 
will  be  explained  later  (122). 

119.  When  from  fissured  nipples  or 
other  causes  it  is  impossible  for  the 
infant  to  nurse,  the  milk  may  be  drawn 
with  a  breast  pump  and  fed  by  bottle  or 
medicine  dropper  for  a  few  days,  until 
a  return  to   breast  feeding  is  possible. 

If  an   abrasion   or  slight  fissure  of  '  lppe    ied' 

the  nipple  causes  much  pain  to  the  mother,  the  use  of  the 
nipple  shield  for  a  day  or  so  may  give  great  comfort  and 
allow  healing  to  take  place.  The  infant  often  rebels 
against  its  use,  however,  from  the  difficulty  of  pulling  the 
milk  through.  The  latter  may  be  partly  obviated  by  fill- 
ing the  shield  with  warm  water  at  the  start,  and  at  the 
same  time  massaging  the  breast,  thus  getting  an  easy 
flow  of  fluid.  Between  nursings  the 
nipple  must  be  carefully  protected. 

120.  Contraindications  for  Nurs- 
ing.— Mothers  with  certain  constitu- 
tional diseases,  especially  tuberculosis, 
should  not  be  allowed  to  nurse  their  offspring.  When 
the  mother  is  pale  and  losing  flesh  and  exhausted  by 
suckling  in  spite  of  tonic  treatment,  the  baby  must  not 
be  continued  on  the  breast.  In  nervous,  excitable  women, 
when  every  effort  has  been  made  to  regulate  the  details 
of  diet   and   living,  and  yet   the   baby   does    not  thrive 


i92  INFANT   FEEDING. 

and    gain    after    a    fair    trial,   it    is    best    to    stop    the 
breast. 

Nursing  after  Menstruation. — The  question  of  nursing 
after  menstruation  has  been  resumed  can  usually  be 
answered  in  the  affirmative.  Any  disturbance  is  usually 
only  temporary  and  may  not  recur  at  the  next  period. 
If,  however,  severe  nervous  and  digestive  disturbances 
regularly  occur  at  each  period  and  interfere  with  the  nu- 
trition of  the  infant,  it  may  be  neces- 
sary to  remove  the  breast  entirely. 
Before  this  is  done  a  trial  may  be  made 
of  giving  the  bottle  during  the  time 
of  menstruation  and  then  resuming 
the  breast. 

Intervening  Pregnancy . — If  preg- 
nancy intervenes  it  is  usually  best  to 
give  the  baby  other  nourishment. 
There  may  be  many  exceptions,  bow- 
ever,  to  this  rule.  Thus,  if  pregnancy 
occurs  during  the  middle  of  a  hot 
summer,  when  the  baby  is  thriving,  or 
in  the  case  of  a  weak  fragile  baby  with 
a  tendency  to  digestive  trouble,  the  breast  may  be  con- 
tinued during  the  early  period  of  pregnancy;  while  not 
ideal,  this  may  prove  the  best  method  of  feeding  available. 
121.  Wet-Nursing. ,— In  many  cases  in  which  a  mother 
cannot  nurse  her  infant,  a  wet-nurse  is  the  best  substitute. 
A  wet-nurse  is  especially  indicated  when  the  infant  is 
poorly  developed  and  shows  signs  of  digestive  feebleness. 
The  preferable  age  for  the  nurse  is  between  twenty  and 
thirty  years,  and  multiparas  usually  do  better  than  primi- 


Fig.  45. — Breast  Pump. 


BREAST   FEEDING.  193 

parse,  the  former  having  had  previous  care  of  the  suckling 
and  general  charge  of  infants,  which  may  be  of  decided 
advantage. 

Too  much  disparity  between  the  ages  of  the  infants 
is  not  desirable,  but  a  woman  whose  infant  is  under  six 
months  can  usually  suckle  a  new-born  baby.  One  advan- 
tage of  having  a  wet-nurse  with  an  older  infant  is  that 
a  careful  inspection  of  the  nurse's  infant  will  show  how 
well  it  has  thriven  upon  her  milk,  and  also  whether  it 
has  derived  any  constitutional  disease,  especially  syphilis, 
from  the  mother.  In  every  case  a  careful  physical  exam- 
ination of  the  applicant,  as  well  as  her  infant,  should  be 
made  by  the  physician.  As  changes  in  the  composition 
of  milk  are  largely  the  result  of  nervous  influences  and 
changes  of  diet,  a  woman  of  quiet,  phlegmatic  tempera- 
ment, in  good  health,  is  to  be  preferred,  and  when  selected 
her  diet  should  be  as  nearly  as  possible  that  to  which  she 
has  been  accustomed,  and  she  should  not  be  allowed  to 
remain  in  idleness.  A  routine  life  should  be  established 
and  maintained,  as  this  will  insure  a  uniform  milk.  The 
nurse's  reward  should  be  in  some  other  form  than  grati- 
fication of  her  inclinations.  This  reward  should  be  held 
out  as  an  inducement  for  her  to  comply  with  directions. 
After  her  services  are  no  longer  required,  she  can  obtain 
what  she  likes  with  the  money  she  has  earned ;  but  if  she 
is  furnished  a  diet  she  is  unaccustomed  to,  she  will  in  all 
probability  over-eat  and  bring  on  either  defective  diges- 
tion or  excretion,  which  will  promptly  disorder  the  diges- 
tion of  the  infant. 

Several  nurses  will  sometimes  have  to  be  tried  before 

a  breast  that  completely  agrees  with  the  baby  is  found. 
13 


i94  INFANT   FEEDING. 

122.  Weaning  and  Mixed  Feeding. — Many  women  who 
are  good  nurses  show  a  deficiency  in  their  milk,  either  in 
quantity  or  quality,  by  the  eighth  or  ninth  month.  The 
bottle  can  here  be  given  with  advantage  several  times 
during  the  twenty-four  hours,  and  especially  at  night,  so 
that  the  breast  can  have  a  prolonged  rest.  The  rate  of 
gain  in  weight  of  the  baby  and  the  health  of  the  mother 
will  be  the  gauge  as  to  when  mixed  feeding  should  be 
begun.  In  any  case  the  baby  should  be  removed  entirely 
from  the  breast  at  the  end  of  the  first  year.  Toward  the 
end  of  lactation  the  milk  becomes  unsuitable  in  composi- 
tion. This  will  be  shown  either  by  digestive  disturbances 
or  loss  of  weight,  or  both,  on' the  part  of  the  baby.  Wean- 
ing should  be  gradual,  and  as  most  babies  will  require  the 
help  of  the  bottle  during  the  latter  part  of  lactation,  it  is 
well  to  begin  as  soon  as  possible  in  giving  one  or  two 
bottle  feedings  each  day ;  the  baby  will  then  be  educated 
in  its  use,  the  mother  will  have  more  time  to  herself,  and 
in  case  of  her  being  ill,  sudden  weaning  will  not  be  neces- 
sary. If  this  method  is  employed,  the  change  from  breast 
feeding  to  bottle  feeding  will  not  cause  inconvenience. 

Examination  and  Modification  of  Breast  Milk. 

i 23.  I n  cases  in  which  the  mother's  milk  does  not  agree 
with  a  baby,  as  shown  by  constant  colic,  or  stationary  or 
losing  weight,  the  breast  should  not  be  withdrawn  until 
every  effort  has  been  made  to  find  out  and  correct  the 
cause  of  the  trouble.  Rotch  has  shown  by  repeated  chem- 
ical analyses  of  mother's  milk  that  much  may  be  accom- 
plished by  altering  the  diet  and  habits  of  life  to  render 
breast  milk,  when  disagreeing,  more  fit    for  any  given 


BREAST   FEEDING. 


195 


1,030 


/ 


\ 


case.  Each  case  must  be  carefully  studied  in  every  detail 
before  finally  deciding  to  remove  the  baby,  from  its 
mothers  breast.  There  is  no  doubt  that  a  large  number 
of  infants  suffer  from  premature  removal ;  often  with  a 
little  care  and  patience  lactation  could  be  continued  dur- 
ing the  normal  term. 

The  careful  studies  and  analyses  of 
Rotch  have  also  shown  that  nervous,  emo- 
tional women,  or  those  who  nurse  their 
infants  at  prolonged  or  irregular  intervals, 
or  too  frequently,  or  who  are  disturbed 
at  night  are  apt  to  furnish  a  poor  milk. 
Regularity  in  diet,  excretion,  exercise, 
rest,  and  nursing  are  always  to  be  insisted 
upon ;  sometimes  it  may  be  necessary  to 
have  the  mother  sleep  in  a  room  where 
she  cannot  be  disturbed  by  the  infant 
for  a  few  nights,  feeding  it  then  by  bottle. 
If,  after  these  precautions  have  been  taken, 
the  milk  continues  to  disagree,  an  analysis 
may  throw  light  on  the  cause  of  the  diffi- 
culty. Many  analyses  of  human  milk  show 
it  generally  to  contain  fat  3  to  5  per  cent, 
proteids  1  to  2  per  cent,  and  sugar  6  to 
7  per  cent.  Undoubtedly  there  is  con- 
stant changing  and  variation  in  these 
percentages  within  certain  limits,  from  day  to  day, 
and  even  from  hour  to  hour,  but  the  infant  usually 
adapts  itself  to  these  variations,  that  doubtless  per- 
form a  useful  function  in  the  nutrition  of  the  child. 
It    is    found    that    variations    are    mostly    in    the    fats 


Fig.  46.  —  From 
Holt's  "Infancy  and 
Childhood."  (Copy- 
right, 1897,  by  D.  Ap- 
pleton  &  Co.) 


196 


INFANT   FEEDING. 


«£ 


C3\ 


and   proteids,   the   sugar   remaining    quite    constant    in 

quantity. 

1.  If  fats  and  proteids  are  both  low  the  infant  is  not 

getting  enough  nourishment,  and  of  course  cannot  gain 
in  weight.  A  more  liberal  diet  for  the 
mother  is  indicated.  2.  If  fats  are  low 
(below  three  per  cent),  and  the  proteids 
normal  (one  to  two  per  cent),  the  mother 
must  be  fed  more  meat,  eggs,  and  milk. 
It  is  useless  to  feed  her  excess  of  fats,  as 
they  will  interfere  with  her  digestion.  3. 
If  proteids  are  high  (above  two  per  cent) 
the  mother's  meat  and  milk  diet  must  be 
cut  down.  4.  If  fat  and  proteids  are  both 
high,  the  diet  must  be  cut  down,  partic- 
ularly the  meats,  and  a  liberal  amount  of 
out-of-door  exercise  must  be  taken.  A 
brisk  walk  of  a  mile  or  two  in  the  open 
air,  twice  daily,  will  sometimes  correct  an 
overrich  milk.  The  physician  must,  how- 
ever, be  specific  in  his  orders,  as  exercise 
to  the  point  of  fatigue  may  be  required 
to  get  results. 

When  a  complete  analysis  of  the  milk 
cannot  be  had,  an  approximate  analysis 
may  be  made  by  the  fat  and  solids  not  fat 
tests,  described  in  the  chapter  on  testing 

cow's  milk.     The  fat  is  determined  by  the  Babcock  test, 

and    the  specific   gravity  with  an    ordinary   urinometer. 

About  an  ounce  of  milk  is  required.     The  entire  contents 

of  a  breast  should  be  removed  and  mixed,  or  very  errone- 


||— 60 


Fig.  47.  —  From 
Holt's  "Infancy  and 
Childhood."  (Copy- 
right, 1897,  by  D.  Ap- 
pleton  &  Co.) 


BREAST    FEEDING. 


1.97 


ous  impressions  will  be  obtained,  as  the  fat  varies  greatly 
in  different  portions  of  the  secretion. 

Holt  has  devised  an  apparatus,  consisting  of  a  cream 
gauge  and  a  small  hydrometer,  for  testing  as  small  a 
quantity  as  one-half  an  ounce  of  breast  milk. 

The  specific  gravity  is  taken  at  yo°  F.,  and  the  milk 
placed  in  the  cream  gauge ;  after  twenty-four  hours  the 
percentage  of  cream  may  be  read.  Five  per  cent  of  cream 
corresponds  to  three  per  cent  of  fat.  The  interpretation 
of  results  is  shown  in  the  following  table  by  Holt: 


Woman's  Milk. 


Specific  gravity,  70°  F. 

Cream — 24  hours. 

Proteids  (calculated). 

1. 03I    

% 

8  to  12$ 

5  to  6fc 

High  (above  10$) 

Low  (below  5%). . 

High 

1.5*. 

Normal  (rich  milk). 

Normal  (fair  milk). 

Normal  or  slightly  be- 
low. 

Very  low  (very  poor 
milk). 

Verv  high  (very  rich 
milk). 

Normal  (or  nearly  so). 

Normal  variations  .  . 

I.O32    

Abnormal  variations 
Abnormal  variations 
Abnormal  variations 

Low  (below  1.02S) 
Low  (below  1.028) 
High  (above  1.032) 
High  (above  1.032) 

Abnormal  variations 

CHAPTER    XX. 

METHODS  OF  SELECTING  FOOD  FOR  ADULTS 
NOT  APPLICABLE  TO  INFANTS— NUTRI- 
TION AND  DEVELOPMENT  OF  THE  DIGES- 
TIVE TRACT  MUST  BE  CONSIDERED  TO- 
GETHER. 

124.  When  it  becomes  impossible  to  supply  an  infant 
with  its  mother's  milk  or  that  of  a  suitable  wet-nurse,  re- 
course must  be  had  to  some  substitute  food.  This  may 
be  done  in  two  ways:  (1)  By  telling  the  mother  or  nurse 
to  try  everything  that  is  suggested  by  kind  friends  until 
something  is  found  that  "  agrees  "  ;  or  (2)  scientifically  to 
adjust  the  food  so  that  the  infant's  future  well-being  will 
be  conserved. 

A.  V.  Meigs,  of  Philadelphia,  made  the  first  attempt  at 
scientific  infant  feeding  by  trying  to  adjust  or  modify 
cow's  milk  so  that  it  would  resemble  mother's  milk  in 
composition.  Later,  Rotch,  of  Boston,  emphasized  the 
importance  of  systematic  "percentage  feeding,"  which 
consists  of  trying  to  make  from  cow's  milk  a  mixture  that 
contains  accurate  percentages  of  fat,  proteids,  carbohy- 
drates, mineral  matter,  and  water,  and  varying  these  per- 
centages to  suit  the  requirements  of  each  particular  in- 
fant. Other  workers  have  contributed  their  quota  to  the 
advancement  of  scientific  infant  feeding  with  the  result 
that  many  formerly  accepted  beliefs  and  doctrines  have 


FOOD    FOR   ADULTS    INAPPLICABLE.  199 

been  modified  or  completely  abandoned.  At  present  it 
is  not  accepted  that  there  is  one,  and  only  one,  way  of  sci- 
entifically feeding  an  infant.  While  there  may  be  differ- 
ences of  opinion  as  to  methods  of  feeding,  there  are  cer- 
tain principles  involved  which  are  beyond  dispute  and 
about  which  there  can  be  only  one  opinion. 

125.  It  has  been  shown  (1)  that  true  growth  consists 
principally  of  an  increase  of  protein  in  the  body  by  a  proc- 
ess of  cell  division  (2),  and  the  addition  of  mineral  mat- 
ter to  the  bones.  (2)  That  protein  cannot  be  elaborated 
by  the  infant,  but  must  be  taken  in  as  such  with  the  food. 
(3)  That  there  are  many  forms  of  protein,  some  of  which 
are  not  tissue  builders  and  can  only  put  off  the  time  when 
death  will  result  from  starvation  (24).  (4)  That  the  first 
demand  of  the  animal  organism  is  for  heat-producing  food, 
and  that  during  starvation  normal  heat  is  kept  up  by  de- 
struction of  the  tissues  (22).  (5)  That  the  function  of 
fat  and  carbohydrates  in  the  body  is   to   produce  heat 

(19). 

It  follows  that  one  of  the  first  problems  of  scientific 
feeding  is  to  determine  the  quantities  and  quality  of  the 
protein  (tissue  builder)  and  fat  and  carbohydrates  (heat 
producers)  needed  for  a  given  individual.  This  problem 
has  been  pretty  well  worked  out  for  adults,  and  is  gener- 
ally performed  as  follows:  1.  From  the  quantity  of  ni- 
trogen in  the  urine  during  a  period  of  fasting  is  deter- 
mined the  amount  of  protein  used  up  daily.  There  is 
no  advantage  in  feeding  more  than  this  quantity  to  an 
adult  as  it  is  only  excreted  (20).  2.  From  the  quantity 
of  oxygen  consumed  is  calculated  the  quantity  of  heat 
produced. 


200  INFANT   FEEDING. 

The  standard  for  measuring  heat  values  in  dietetics  is 
called  a  large  calo7rie  and  is  the  amount  of  heat  required 
to  raise  the  temperature  of  one  litre  of  water  (2.2  lbs.) 
i°  Cor  i.8°  F. 

The  heat  produced  by  the  combustion  of  1  gm.  of 
protein  is  about  4.1  calories;  of  1  gm.  of  carbohydrates, 
about  4.1  calories;  of  1  gm.  of  fat,  about  9.3  calories,  or 
about  two  and  one-quarter  times  that  of  either  protein  or 
carbohydrates. 

It  has  been  found  that  a  man  doing  ordinary  muscu- 
lar work  requires  daily  about  125  gm.  (=  4  oz.)  of  protein 
and  enough  other  food  to  produce  about  3,000  calories. 
In  selecting  the  food  for  such  a  man  it  is  only  necessary, 
theoretically,  to  see  that  his  food  contains  125  gm.  of 
digestible  protein  and  enough  heat-producing  food  to  pro- 
duce 3,000  calories.  Adding  the  results  obtained  by  mul- 
tiplying by  4.1  the  weight  in  grams  of  the  protein  and 
carbohydrates,  and  by  9.3  that  of  the  fat  contained  in  any 
food,  will  give  the  total  number  of  calories  it  will 
produce. 

Tables  have  been  prepared  showing  the  composition 
of  most  articles  of  food  in  general  use,  expressed  in  per- 
centages of  digestible  protein,  fat,  and  carbohydrates, 
and  it  is  a  simple  matter  to  calculate  from  these  an- 
alyses the  quantities  required  properly  to  nourish  a 
person. 

For  a  healthy  adult  there  are  many  articles  of  diet  that 
are  interchangeable,  weight  for  weight  almost,  as  their 
composition  and  digestibility  are  practically  the  same ;  for 
this  reason  it  makes  little  difference  which  article  is 
used. 


FOOD    FOR   ADULTS    INAPPLICABLE. 


201 


The   following    analyses   by   Atwater   illustrate    this 
statement: 


Corned  rump  of  beef. 

Turkey 

Shoulder  of  veal 

Halibut 


Fat,  per  cent. 

5-i 
5-9 
7-9 
4-4 


In  preparing  food  for  infants  this  method  of  selecting 
food  cannot  be  employed,  as  will  be  explained  further  on. 

The  proportion  between  the  digestible  protein  and 
heat-producing  elements  in  food  is  called  the  nutritive 
ratio  and  is  thus  determined.  As  fat  has  about  two  and 
one-quarter  times  as  much  fuel  value  as  carbohydrates, 
the  weight  of  the  fat  is  multiplied  by  two  and  one-quarter 
and  added  to  the  weight  of  the  carbohydrates.  The  pro- 
portion between  the  weight  of  the  protein  and  the  weight 
of  the  heat  producers,  calculated  as  carbohydrates,  is  the 
nutritive  ratio. 

Example.     A  food  contains: 

Fat,  2  per  cent ;  protein,  io  per  cent ;  carbohydrates,  50  per  cent. 
Fat,  2  per  cent  X  2^  =    4.5  per  cent,  equivalent  in  carbohydrates. 
Carbohydrates,  =  50.0  per  cent 


Nutritive  ratio,  1-5.45. 


54.5  per  cent  -=-  10  per  cent  protein  =  5.45. 


This  is  about  the  ratio  required  by  adults. 

There  is  a  wider  nutritive  ratio  in  human  milk,  which 
w7e  should  strive  to  imitate,  than  in  an  adult's  food,  as  can 
be  seen  by  a  glance  at  analyses  of  this  milk  that  are 
within  the  range  of  variation : 

Human  Milk. 


Fat,  per  cent. 


Proteid,  per  cent. 


Sugar,  per  cent. 


Nutritive  ratio,  1-12.75. 
Nutritive  ratio,  1-8. 


202  INFANT   FEEDING. 

In  human  milk  not  only  is  there  a  variation  in  compo- 
sition, but  also  in  the  nutritive  ratio.  The  much  greater 
proportion  of  heat-producing  elements  in  the  infant's  nat- 
ural food  than  in  the  adult's  food  is  in  part  accounted 
for  by  the  fact  that  there  is  a  much  greater  radiation  of 
heat  from  an  infant's  body ;  metabolism  is  also  much  more 
active. 

At  first  thought  nothing  seems  more  rational  in  arti- 
ficial infant  feeding  than  taking  the  milk  of  some  of  the 
lower  animals  and  adjusting  the  percentages  of  fat,  pro- 
teids,  and  sugar,  and  the  nutritive  ratio,  so  that  they  shall 
approximate  those  of  human  milk.  Adjusting  diets  for 
adults  on  this  percentage  and  nutritive  ratio  plan  is  very 
successful,  but  unfortunately  not  so  successful  in  feeding 
infants,  as  it  is  often  impossible  for  a  young  infant  to 
digest  the  same  percentage  of  the  proteids  of  cow's  milk 
as  is  found  in  woman's  milk. 

In  feeding  adults,  in  whose  fully  developed  digestive 
systems  a  great  variety  of  foods  can  be  digested  equally 
well,  it  is  only  necessary  to  see  that  enough  of  fat,  pro- 
teids, and  carbohydrates  are  furnished  to  maintain  the 
body. 

In  feeding  infants  or  young  animals,  whose  digestive 
systems  are  not  fully  developed,  it  is  not  only  necessary 
to  supply  the  proper  quantities  of  nutritional  elements, 
which  include  more  ingredients  than  fat,  proteids,  carbo- 
hydrates, and  mineral  matter,  but  they  must  be  in  such 
form  as  normally  to  develop  the  digestive  tract. 

It  has  been  shown  in  chapters  IV.  and  VIII.  that  the 
milk  of  each  species  of  animal  is  highly  specialized  for  these 
two  purposes.     For  these  reasons  it  is  not  to  be  expected 


FOOD    FOR   ADULTS   INAPPLICABLE. 


203 


that  a  perfect  substitute  for  human  milk  will  ever  be  pro- 
duced. The  most  that  can  be  done  is  to  provide  a  food 
whose  composition  is  as  nearly  like  human  milk  as  our 
imperfect  knowledge  of  milk  permits  us,  to  make,  and  to 
have  it  in  such  form  that  it  will  allow  a  normal  use  and 
development  of  the  digestive  tract. 

126.  Development  of  the  Digestive  Tract. — When  an 
infant  or  any  young  suckling  animal  is  born  it  has  never 
used  its  digestive  system, 
its  nourishment  having 
been  received  from  its 
mother's  blood  stream. 
For  the  first  few  days 
afterbirth  the  mammary 
glands  do  not  secrete 
milk,  but  colostrum, 
which  is  quite  another 
thing.  The  function  of 
colostrum  seems  to  be 
to  start  up  the  digestive 
process,  as  there  is  a 
gradiial  change  from  colostrum  which  requires  little  di- 
gestion, into  milk  which  requires  digestion.  This  change 
has  been  better  studied  in  cow's  colostrum  than  in  that 
of  other  animals,  for  obvious  reasons. 

The  composition  and  character  of  the  ingredients  of 
cow's  colostrum  are  different  from  those  of  milk  (34). 
The  proteids  which  are  very  high  in  quantity  are  not 
principally  casein  as  in  milk,  which  curds  under  the  action 
of  the  rennet  secreted  in  the  stomach  and  requires  con- 
siderable digestive  effort,  but  are  a  mixture  consisting 


48.— Colostrum  Bodies.  (X  300.)  a',  Cells 
with  nucleus  ;  a,  cells  undergoing  fatty  degenera- 
tion ;  i>,  cells  containing  large  drops  of  fat  ;  <r,  cells 
with  a  partially  destroyed  cell  membrane  ;  d,  e,  and_/", 
cells  which  have  entirely  lost  the  cell  membrane  ;  g; 
cell  masses  from  the  milk  canals.     ( Aikman.) 


204 


INFANT   FEEDING. 


principally  of  albumins,  globulins,  albumoses,  and  pep- 
tones which  are  absorbed  with  little  digestive  effort  and 
do  not  curd.  Furthermore,  the  stomach  of  a  calf  under 
three  days  old  secretes  very  little  rennet.  The  sugar  of 
colostrum  is  said  to  be  principally  dextrose,  the  sugar 
found  in  the  blood  stream.  A  peculiar  and  distinguish- 
ing constituent  of  all  kinds  of  colostrurii  is  the  colostrum 


Fig.  49. — Normal  Human  Milk.      (Jewett.) 


Fig.  50. — Colostrum  Corpuscles.     (Jewett.) 


corpuscles,  which  are  thought  by  some  to  be  modified 
white  blood  corpuscles. 

For  a  week  or  two  after  birth  there  is  a  continual 
gradual  change  in  the  character  of  the  proteids  and  sugar 
of  the  mammary  secretion,  the  constituents  of  normal 
milk  which  require  digestion,  displacing  those  of  colos- 
trum ;  during  the  same  time  the  secretion  of  the  digestive 
juices  commences  in  the  young  animal. 

This  process  seems  to  take  place  in  all  animals  that 
secrete  milk,  but  when  the  flow  of  milk  is  established  a 
wide  diversification  in  digestive  processes  and  character 
of  the  milk  is  seen.     The  milk  of  animals  whose  digestion 


FOOD   FOR  ADULTS   INAPPLICABLE.         205 

takes  place  principally  in  the  stomach  forms  solid  curds 
that  leave  it  with  difficulty  (cow's,  goat's,  and  sheep's 
milk). 

The  milk  of  animals  whose  digestion  is  principally  in- 
testinal forms  soft  gelatinous  curds  which  easily  pass  into 
the  intestine  (mare's  and  ass'  milk). 

The  human  digestive  tract  stands  between  these  two 
types,  and  consequently  neither  cow's  nor  ass'  milk  fits  it. 

Function  of  Colostrum. — Colostrum  seems  to  have  the 
following  functions: 

1  st.  To  cause  a  discharge  of  meconium,  the  contents 
of  the  foetal  intestine,  so  that  food  can  pass  in  and  be 
absorbed. 

2d.  By  the  large  proportion  of  easily  absorbable  forms 
of  protein  and  sugar  it  contains  to  start  up  the  absorptive 
process  and  nourish  the  infant. 

3d.  By  the  gradual  substitution  of  protein  and  sugar 
that  require  digestion,  to  stimulate  the  flow  of  the  diges- 
tive juices. 

Thus  far  the  process  of  development  has  been  confined 
to  absorption  and  the  chemical  part  of  digestion.  When 
normal  milk  is  secreted  it  curds  in  such  form  that  it  will 
develop  the  digestive  tract  in  its  preparatory  or  mechan- 
ical action.  After  this  process  has  proceeded  for  a  time 
teeth  appear,  and  the  preparatory  portion  of  the  digestive 
tract  is  still  further  developed.  In  infants  this  process  of 
development  of  the  digestive  tract  continues  during  two 
or  three  years,  so  it  is  manifestly  out  of  the  question  to 
use  the  methods  of  selecting  for  infants  foods  that  are 
adapted  for  adults. 

It  must  be  clearly  borne  in  mind  in  infant  feeding  that 


206  INFANT   FEEDING. 

nutrition  and  development  of  the  digestive  tract  must  be 
considered  together.  Little  progress  will  be  made  if  only 
a  calculation  of  the  composition  of  food  is  made.  This 
is  a  small  part  of  scientific  infant  feeding,  although  by 
many  writers  on  the  subject  an  undue  amount  of  atten- 
tion has  been  given  it,  which  has  made  infant  feeding 
appear  to  be  a  complicated  subject.  As  a  matter  of  fact, 
when  the  principles  of  artificial  infant  feeding  are  grasped, 
the  process  becomes  as  simple  as  diluting  condensed  milk, 
and  the  most  scientific  food  that  can  be  conceived  can  be 
prepared  in  any  home  with  very  little  effort. 

The  principles  of  preparing  infant  food  will  be  con- 
sidered in  the  next  chapter. 


CHAPTER    XXI. 

GENERAL     CONSIDERATIONS     IN     PREPARING 
INFANT'S   FOOD. 

Breast  Milk  as  Pattern — Effect  of  High  and  Low 
Protein — Value  of  Percentage  Feeding — Cream 
and  Milk  Mixtures— Bottled  Milk — Top  Milk 
— Diluents. 

127.  In  preparing  an  artificial  food  for  infants  nature 
should  be  followed  as  closely  as  possible.  The  food  should 
compare  with  human  milk  in  its  nutritive  value,  which  is 
determined  by  chemical  analysis,  in  physiological  proper- 
ties, or  its  behavior  in  the  digestive  tract,  and  in  the  man- 
ner and  condition  in  which  it  is  supplied  to  the  infant. 

In  composition,  human  milk  is  variable,  but  it  is  gen- 
erally believed  that  it  contains  as  a  rule  between  3  per 
cent  and  5  per  cent  of  fat,  1  per  cent  and  2  per  cent  of 
proteid,  6  per  cent  and  7  per  cent  of  sugar,  and  0.2  per 
cent  and  0.3  per  cent  of  mineral  matter.  No  attempt  is 
made  to  take  account  of  its  other  ingredients.  In  its 
physiological  properties  it  is  specially  adapted  for  de- 
veloping the  infant's  digestive  tract,  owing  to  the  char- 
acter of  its  protein. 

There  has  been  a  great  deal  of  discussion  as  to  what 
forms  of  protein  exist  in  human  milk.  Chemists  have 
not  agreed  on  this  point  and  with  improved  methods  of 
analysis  different  results  are  continually  being  obtained. 


208  INFANT    FEEDING. 

Some  authors  call  the  protein  of  milk  casein  or  caseinogen 
and  lactalbumin,  and  many  analyses  have  been  published 
showing  the  percentages  of  these  ingredients.  Other 
chemists,  using  later  and  improved  methods,  have  found 
large  quantities  of  other  forms  of  protein,  especially  in 
woman's  milk;  also  that  the  casein  of  human  milk  has 
not  the  same  properties  as  that  in  other  milks.  Varying 
results  have  also  been  obtained  in  examination  of  the 
sugar  of  milk  (28). 

Though  the  composition  of  the  milk  of  any  animal  is 
variable  and  no  definite  conclusion  can  be  reached  as  to 
the  character  of  the  protein  of  different  milks,  one  char- 
acteristic stands  out  clearly,  and  that  is,  the  protein  of 
each  milk  is  especially  adapted  for  the  digestive  tract  it 
was  intended  to  supply.  Though  young  animals  readily 
tolerate  a  variation  in  quantities  of  the  protein  of  their 
natural  milk,  they  are  promptly  disturbed  when  the  pro- 
tein of  the  milk  of  another  type  is  supplied  to  them.  The 
fats  and  sugars  cause  little  trouble.  As  all  young  animals 
thrive  on  their  mothers'  milk  irrespective  of  its  type,  and 
as  all  animal  life  requires  the  same  ultimate  food  elements, 
the  differences  between  the  milks  of  different  animals 
must  be  more  physiological  than  chemical. 

None  of  the  lower  animals  furnishes  a  milk  that  ap- 
proximates human  milk  in  physiological  properties  even 
after  the  percentages  of  fat,  proteids,  and  sugar  have  been 
adjusted  to  equal  those  of  human  milk.  In  the  breast 
the  ingredients  of  the  milk  are  not  secreted  uniformly, 
the  greater  quantity  of  fat  being  in  the  latter  part  of  the 
flow;  furthermore,  the  milk  has  not  undergone  bacterial 
changes. 


PREPARING   INFANT'S    FOOD.  209 

In  feeding  an  infant  artificially  it  is  impossible  to 
secure  a  food  whose  ingredients  have  the  same  physio- 
logical properties  as  those  of  human  milk,  to  imitate  the 
process  of  secretion,  or  generally  to  obtain  milk  free  from 
bacterial  change.  Therefore  it  should  always  be  kept  in 
mind  that  any  thing  aside  from  breast  milk  that  is  put  into 
an  infant's  stomach  is  a  foreign  substance  that  may  cause 
digestive  disturbance.  This  is  one  of  the  fundamental 
principles  of  infant  feeding. 

128.  Though  nutrition  and  development  of  the  diges- 
tive tract  should  be  considered  together,  nutrition  comes 
first,  and  in  cases  of  poor  digestion  it  is  justifiable  to  use 
anything  that  will  sustain  the  infant  until  normal  digestion 
is  re-established ;  then  the  food  should  be  changed  so  as 
to  cause  proper  development.  Many  feel  that  after  some- 
thing that  "  agrees  "  and  causes  gain  in  weight  is  foundT 
the  problem  of  successful  feeding  has  been  solved ;  but  the 
future  of  the  infant  may  be  completely  wrecked  by  such 
a  method  of  feeding.  For  instance,  an  infant  is  receiv- 
ing as  much  fat  and  sugar  as  is  found  in  human  milk  and 
only  one-fourth  to  one-half  as  much  protein.  The  infant 
is  fat  and  gaining  in  weight,  and  to  all  appearances 
healthy,  yet  it  can  be  predicted  with  reasonable  certainty 
that  this  infant  will  become  rachitic  or  succumb  to  the 
first  serious  illness.  As  resisting  force  comes  from  the 
protein  of  the  food,  it  is  apparent  that  a  bottle-fed  infant 
who  receives  but  one-fourth  to  one-half  as  much  protein 
as  a  breast-fed  infant  will  not  be  so  rugged  or  will  have 
as  good  a  chance  of  surviving.  What  a  difference  a  too 
small  amount  of  protein  in  the  food  of  a  growing  animal 

will  have  on  the  tissues  and  health  of  the  adult  has  been 
14 


210  INFANT    FEEDING. 

shown  by  W.  A.  Henry,  of  the  Wisconsin  Experiment 
Station. 

It  had  been  noticed  that  pigs  that  were  fed  on  a  diet 
rather  low  in  protein  readily  succumbed  to  disease.  They 
were  very  fat,  but  when  slaughtered  yielded  a  relatively 
small  amount  of  lean  meat  or  muscular  tissue.  To  de- 
termine the  effect  of  rich  and  poor  protein  diet  on  the 
bones  and  tissues  Henry  and  others  made  some  extended 
experiments.  A  number  of  healthy  young  pigs  were 
selected ;  part  were  reared  on  a  diet  low  in  protein  and 
the  others  on  a  diet  high  in  protein.  At  maturity  both 
lots  were  slaughtered  and  their  bodies  analyzed. 

The  following  figures  from  Henry  will  give  an  idea  of 
the  immense  advantage  to  a  growing  animal  of  a  diet 
high  in  protein.  After  an  animal  has  matured  there  is 
no  such  advantage. 

Blood  per  ioo  pounds  weight : 

High  protein  diet 51.2  ounces. 

Low  protein  diet 36. 8        " 

Liver  per  100  pounds  weight : 

High  protein  diet 48.4  ounces. 

Low  protein  diet 31-9        " 

Muscular  tissue  : 

One  third  more  on  high  protein  diet. 
Strength  of  bone  : 

High  protein  diet.      Thigh  bone  broke  at  503  pounds  pressure. 

Low  protein  diet.       Thigh  bone  broke  at  380  pounds  pressure. 

It  will  be  seen  that  a  food  that  causes  gain  in  weight  is 
not  necessarily  a  good  food  for  an  infant.  The  scales  are 
not  a  safe  guide  by  themselves  in  judging  of  an  infant's 
development. 

It  is  right  here  that  thinking  in  percentages,  as  advo- 
cated by  Rotch,  is  of  the  greatest  value.     It  enables  any 


PREPARING    INFANT'S    FOOD.  211 

one  readily  to  compare  the  nutritional  value  of  a  substi- 
tute food  with  that  of  human  milk.  There  is  nothing 
complicated  about  it.  All  that  is  necessary  is  to  have  a 
general  idea  of  the  composition  and  digestibility  of  vari- 
ous foods  that  are  used  in  infant  feeding.  For  instance, 
human  milk  contains  nearly  2  per  cent  of  protein,  and 
cow's  milk  diluted  three  times  about  1  per  cent ;  it  is  evi- 
dent, therefore,  that  an  infant  that  is  getting  this  diluted 
milk  will  receive  only  about  half  as  much  tissue-building 
food  as  the  infant  that  gets  breast  milk.  If  in  the  human 
milk  there  was  about  4  per  cent  of  fat  and  7  per  cent  of 
sugar,  the  breast-fed  infant  would  have  an  immense  ad- 
vantage over  the  infant  getting  the  cow's  milk  diluted  three 
times,  which  would  contain  only  about  1.3  per  cent  of  fat 
and  1.3  per  cent  of  sugar.  In  all  probability  the  breast- 
fed infant  would  be  gaining  in  weight  and  strength  while 
the  bottle-fed  baby  would  be  weak,  puny,  and  losing  in 
weight.  Under  the  old  haphazard  methods  of  feeding  it 
would  have  been  thought  that  this  baby  could  not  thrive 
on  fresh  cow's  milk  and  it  would  have  been  fed  on  some 
proprietary  food  or  condensed  milk,  with  possibly  a 
prompt  gain  in  weight  as  a  result,  for  reasons  that  will  be 
given  later.  Under  modern  methods  of  thinking  it  would 
be  known  at  a  glance  that  the  great  trouble  with  the 
diluted  cow's  milk  lay  in  its  not  supplying  enough  heat 
and  energy-producing  food.  It  could  not  be  expected 
that  getting  only  one-half  the  quantity  of  protein  and  one- 
quarter  of  the  quantity  of  heat-producing  food  found  in 
breast  milk  the  bottle-fed  infant  could  thrive.  In  the 
proprietary  foods  and  condensed  milk,  as  usually  prepared 
for  the  infant,  there  is  a  larger  quantity  of  heat-producing 


212  INFANT   FEEDING. 

food  (sugar)  than  is  used  up,  which  enables  the  infant  to 
lay  on  fat  and  not  use  the  protein  for  fuel ;  the  result  is 
gain  in  weight.  If  sugar  had  been  added  to  the  diluted 
cow's  milk,  gain  in  weight  would  also  have  followed. 

129.  The  problem  of  infant  feeding  does  not  consist 
simply  of  supplying  protein  and  heat-producing  food,  of 
which  sugar  is  a  good  example.  Fat  of  milk  contains 
lecithin,  which  is  an  important  constituent  of  the  nervous 
system,  so  it  is  necessary  to  see  that  an  infant's  food  con- 
tains an  amount  of  milk  fat  equal  to  that  found  in  human 
milk,  particularly  as  cow's  milk  contains  less  lecithin  than 
human  milk.  As  stated  in  the  previous  chapter  and  in 
chapter  IV.,  the  curding  of  milk  is  for  the  purpose  of  de- 
veloping the  digestive  tract,  so  it  is  essential  that  the  basis 
of  an  infant's  food  should  be  the  milk  of  some  other  ani- 
mal, although  there  is  no  milk  that  is  exactly  like  human 
milk  in  curding  properties.  Though  other  forms  of 
protein  will  nourish  an  infant,  they  do  not  cause  its  di- 
gestive tract  to  develop  naturally. 

Cow's  milk,  which  must  be  the  basis  of  an  artificial 
infant-food,  was  intended  to  nourish  a  calf  that  grows 
much  more  rapidly  than  an  infant,  and  therefore  contains 
much  more  protein  than  human  milk.  This  protein  was 
also  intended  for  digestion  in  the  stomach  and  forms  solid 
curds  which  cannot  readily  leave  the  stomach.  In  an  in- 
fant digestion  takes  place  principally  in  the  intestine,  and 
human  milk  is  especially  adapted  for  easily  leaving  the 
infant's  stomach.  In  the  calf  and  cow,  digestion,  which 
takes  place  principally  in  the  stomach,  is  prolonged,  so 
when  cow's  milk  is  put  into  the  infant's  stomach  it  is  not 
to  be  wondered  at  that  it  slowly  leaves  the  stomach,  or 


PREPARING   INFANT'S   FOOD.  213 

that  curds  are  vomited  or  appear  in  the  stools.  This 
curd  question  has  been  before  infant  feeders  ever  since 
cow's  milk  began  to  be  used  for  infant  feeding,  and  prob- 
ably always  will  be. 

To  reduce  the  quantity  of  protein  in  the  infant's  food 
and  also  to  modify  the  character  of  the  curd,  milk  is 
diluted  with  various  substances  which  will  be  described 
later.  This  diluting  reduces  the  fat  and  sugar  and  they 
must  be  added  if  the  food  is  at  all  to  approximate  human 
milk  in  composition. 

In  many  methods  of  preparing  infant's  food  it  has 
been  recommended  that  certain  quantities  of  cream  of 
assumed  richness  be  mixed  with  milk  to  increase  the  fat, 
and  the  mixture  then  diluted ;  for  each  infant  a  special 
formula  had  to  be  calculated  which  was  burdensome,  and 
besides  cream  is  so  inconstant  in  composition  that  no  ac- 
curacy could  be  insured  no  matter  how  exactly  the  calcu- 
lations were  made.  If  centrifugal  cream  (43)  was  used, 
the  emulsion  of  the  fat  was  destroyed  and  there  was  a 
separation  of  the  proteids  (45) ;  if  gravity  cream  was  used, 
the  cream  might  be  nearly  twice  as  rich  or  only  one-half 
as  rich  as  it  was  thought  to  be.  Where  one  infant  thrived 
on  a  formula,  another  that  apparently  needed  the  same 
food  was  completely  upset  by  it  when  prepared  from  dif- 
ferent milks  and  creams.  In  one  instance  to  which  the 
author's  attention  was  called,  it  was  calculated  that  the 
infant  was  getting  four  per  cent  fat ;  an  assay  showed  nine 
per  cent,  which  explained  an  attack  of  indigestion.  Many 
of  the.  unsatisfactory  results  that  have  followed  the  use  of 
cream  and  milk  mixtures  might  have  been  avoided  and 
much  simpler  methods  of  preparing  food  used  had  there 


214  INFANT   FEEDING. 

been  a  better  general  understanding  of  the  nature  and 
composition  of  milk  and  cream. 

130.  It  is  widely  believed  that  cow's  milk  contains  fat 
4  per  cent,  proteids  4  per  cent,  sugar  4  per  cent,  and 
gravity  cream  fat  16  per  cent,  and  about  the  same  quantity 
of  proteid  and  sugar  as  whole  milk.  Now  it  is  known 
that  milk  may  contain  anywhere  from  3  per  cent  to  5  per 
cent  of  fat,  from  3  per  cent  to  4  per  cent  of  proteids,  and 
from  4  per  cent  to  7  per  cent  of  sugar;  and  gravity  cream 
as  low  as  10  per  cent  and  as  high  as  28  per  cent  of  fat,  so 
it  is  not  to  be  wondered  at  that  widely  differing  results 
were  obtained  with  mixtures  made  after  the  same  formula 
but  with  different  milks  and  creams  (38). 

One  of  the  reasons  that  condensed  milk  is  so  popular 
as  an  infant's  food  is  the  ease  with  which  it  can  be  pre- 
pared for  the  infant's  bottle;  simply  mix  so  much  con- 
densed milk  and  so  much  diluent.  Any  quantity  can  be 
made  up;  enough  for  one  feeding  or  for  all  day.  Now  it 
is  almost  as  easy  to  prepare  from  fresh  cow's  milk  a  food 
containing  the  quantities  of  fat,  proteids,  and  sugar  that 
are  within  the  range  of  those  found  in  human  milk  by  the 
method  about  to  be  described. 

131.  In  human  milk  there  is  from  two  to  three  times 
as  much  fat  as  proteid.  In  cow's  milk  the  quantities  of 
fat  and  proteid  are  about  equal.  If  cow's  milk  is  allowed 
to  stand  for  any  length  of  time,  the  fat,  being  lighter  than 
the  other  ingredients  of  the  milk  serum,  will  rise  to  the 
surface  as  cream.  Whereas  before  the  cream  rose  the 
quantity  of  fat  and  proteid  in  the  milk  was  uniform 
throughout  the  entire  quantity  of  milk,  it  is  now  apparent 
that  in  the  upper  creamy  portion  there  will  be  many  more 


PREPARING   INFANT'S    FOOD.  215 

times  as  much  fat  as  proteid.  If  in  this  upper  milk  there 
can  be  found  a  quantity  which  will  uniformly  contain  be- 
tween two  and  three  times  as  much  fat  as  proteid,  prepar- 
ing the  infant's  food  will  be  a  simple  matter,  requiring 
only  the  removal  of  this  quantity  from  the  top,  diluting  it, 
and  adding  sugar.  By  the  use  of  bottled  milk  such  a 
method  can  be  carried  out  anywhere  with  the  greatest 
ease  and  with  the  best  results.  Before  describing  the 
method  in  detail  an  explanation  of  the  advantages  and 
composition  of  bottled  milk  will  be  given. 

132.  It  has  been  shown  that  the  bacteria  which  get 
into  milk  do  not  grow  to  any  extent  if  the  temperature  is 
below  500  F.  (60,  65),  and  that  cream  rises  rapidly  if  the 
milk  is  quickly  cooled  to  below  this  point  immediately 
after  milking  (41).  If  as  soon  as  possible  after  milking  the 
mixed  milk  of  several  cows  is  bottled  and  kept  cool,  the 
low  temperature  will  retard  the  growth  of  bacteria  and 
cause  the  cream  to  rise ;  thus  when  this  milk  is  delivered 
to  families  it  will  be  fairly  free  from  bacterial  change  and 
in  condition  to  use  at  once  in  preparing  the  infant's  food, 
and  will  not  vary  much  in  composition  from  day  to  day. 

It  is  a  remarkable  fact  that  in  bottled  milk  there  is 
generally  about  the  same  quantity  of  cream  no  matter 
how  rich  the  original  milk  was ;  but  the  richness  of  the 
cream  varies  greatly.  One  day  the  author  liad  purchased 
nine  quarts  of  bottled  milk  on  which  the  cream  had  risen. 
When  set  in  a  row  there  was  hardly  any  perceptible  dif- 
ference in  the  depth  of  the  layer  of  cream  in  any  of  the 
bottles. 

The  milk  and  cream  were  then  tested  for  fat.  The 
poorest  milk  contained  3.1  per  cent  fat  and  the  richest 


2l6 


INFANT   FEEDING. 


4.6  per  cent.  The  poorest  cream  contained  11.2  per  cent 
fat  and  the  richest  23  per  cent.  At  other  times  creams 
poorer  and  richer  in  fat  were  obtained. 

The  range  of  composition  of  whole  milk  before  and 
after  the  cream  has  risen  can  be  seen  by  a  glance  at  the 


following  illustration: 

QUART  BOTTLE  OF  MILK 
BEFORE  CREAM  HAS  RISEN 


QUART  BOTTLE  OF  MILK 
AFTER  CREAM  HAS  RISEN 


FAT  3f<  TO  5< 

PROTEIDS    3 "  TO  4^ 
SUGAR  M  TO  5- 


FAT  AND   PROTEIDS  ARE 

NEARLY  EQUAL  EXCEPT  IN 

VERY  RICH  MILKS 


GRAVITY  CREAM 

CONTAINS  104  TO  24^  FAT 


151 OZ. 


2N°0Z. 


REMAINING  MILK 

OR 

SKIM  MILK 

FAT  .5r  TO  1.5^ 

PROTEIDS    3    TO  44 
SUGAR  4?  TO  6* 


3R?0Z. 


4™oz. 


5iyoz. 


6™0Z. 


7™0Z. 


8™0Z. 


9IH0Z. 


26™0Z. 


Figs.  51  and  52. — Milk  Before  and  After  Cream  has  Risen. 

The  richness  of  the  cream  in  fat  depends  a  great  deal 
on  the  size  of  the  fat  globules.  In  milks  poor  in  fat  the 
globules  are  very  small    (36)  and  rise  slowly,  hence  cream 


PREPARING   INFANT'S   FOOD. 


217 


from  such  milk  is  thin  and  bulky.  In  milks  rich  in  fat  the 
globules  are  larger  and  have  greater  buoyancy,  hence  they 
rise  quickly  and  with  some  force.  Cream  from  such  milk 
is  very  dense  near  the  top.    For  these  reasons  the  layer  of 


ONE  QUART  MILK 

4.1%  FAT 

WITH  CREAM  RISEN 


LAYER  OF  CREAM 

NOT  UNIFORM  IN 
COMPOSITION 


LAYERS  OF  CREAM   NOT  UNIFORM 
IN  COMPOSITION. 


FAT  IN  EACH  OUNCE. 


2NDQZ. 


35P0Z. 


4IH0Z. 


|SJ0Z.  CONTAINS  25^  FAT 


FAT  IN  DIFFERENT  PORTIONS 

REMOVED  FROM  THE  TOP 

AND  MIXED. 


23f<     " 

TOP    2  OZS. MIXED 

24  £  FAT 

19  $     " 

"      3  OZS.      " 

22.5J?  rt 

18.5^  " 

"       4  OZS.      " 

21.4^  " 

10.5^  " 

"       5  OZS.     " 

19.2^" 

\M  " 

"      6  OZS.      " 

16.8^" 

3.4$  " 
2.2$6  " 
1.8^  " 
\M  " 

"       7  OZS.      " 
"      8  OZS.      " 
"       9  OZS.      " 
"     10  OZS.      " 

15.0^" 
13.3^  " 
11.5;*  " 

10.5^  " 

1.2$»    "  ' 

"     12  OZS.      " 

9.05*  " 

1.2^   " 

"     14  OZS.      " 

7.8^-' 

\.Z$  " 

"     16  OZS.     " 

7.0,^  " 

1.2JS   " 

"     18  OZS.      " 

6.3^  " 

1.2^    " 

"    20  OZS.      " 

5.8^" 

1.2£   " 

"    22  OZS.      " 

5.4^" 

l.2ys.  " 

"    24  OZS.      " 

5.0,1  " 

\.2i    " 

"    26  OZS.      " 

4.7^  " 

\.Z$    " 

"    28  OZS.      " 

4.5^  " 

\.2?c    " 

"    30  OZS.      " 

4.3^  " 

1.2"»    " 

ALL  MIXED 

4.1£  " 

Fig.  53.— Showing  Distribution  of  Fat  in  Bottled  Milk  After  Cream  has  Risen. 

cream  in  the  bottles  is  not  at  all  uniform  in  composition, 

it  being  sometimes  two  or  three  times  as  rich  in  fat  near 

the  surface  as  near  the  junction  with  the  remaining  milk. 

The  illustration  above  shows  how  the   fat  varies   in 


218 


INFANT   FEEDING. 


different  portions  of  the  creamy  layer.  This  milk  had 
been  passed  through  a  centrifugal  machine  to  remove 
dirt,  and  hence  there  was  not  so  complete  a  separation  of 
fat  (42)  as  would  have  taken  place  in  natural  milk,  as 
shown  by  the  high  percentage  of  fat  in  the  skimmed  milk, 
which  is  not  usual. 

The  table  at  the  right  of  the  bottle  shows  the  composi- 
tion of  different  quantities  of  the  cream  when  mixed ;  also 
of  mixtures  of  all  the  cream  ard  varying  quantities  of  the 
remaining  milk.  It  will  be  noticed  that  every  ounce  of 
remaining  milk  that  is  added  to  the  cream  reduces  the 
quantity  of  fat  in  the  mixture  and  that  a  great  many  mixt- 
ures, each  containing  a  different  quantity  of  fat,  can  be 
had  from  one  bottle  of  milk.  Glancing  along  this  table 
it  will  be  seen  that  the  top  nine  ounces  contain  11.5  per 
cent  of  fat,  or  about  three  times  that  of  the  whole  milk, 
and  the  top  16  ounces  7  per  cent,  or  nearly  two  times  that 
of  whole  milk.  These  proportions  hold  good  with  any 
milk  rich  or  poor,  but  the  percentages  of  fat  will  vary,  as 
shown  by  the  following  assays  of  poor,  medium,  and  rich 
milk : 


Fat — per  cent. 


Whole  milk 

Top    6  ounces 

7 

"      S 

"  9 

"  10  " 

"  11  " 

"  12  " 

"    13        " 
"    14 
"    15 
"    16 
Skim  milk  .  .  . 


3-i 


4.2 


4.8 


13-4 
11. 6 

10.2 
9.2 
3.4 
7-7 
7-i 
6.6 
6.2 
5-8 
5-5 


19.0 

23.0 

16.4 

19.8 

14. 1 

17.3 

12.6 

15-5 

11. 4 

13-9 

10.4 

12.7 

9.6 

11. 7 

9.0 

10.8 

8.3 

10.0 

7-3 

9-4 

7-4 

9.0 

.6 

■4 

PREPARING   INFANT'S    FOOD.  219 

Milk  poor  in  fat  yields  top  milk  poor  in  fat.  Milk 
rich  in  fat  yields  top  milk  rich  in  fat.  This  does  not 
complicate  matters;  as  rich  milk  is  diluted  more  than 
poor  milk,  so  rich  top  milk  is  to  be  diluted  more  than 
poor  top  milk. 

The  next  step  is  to  see  what  separation  takes  place  in 
the  proteids  and  sugar,  or  solids  not  fat,  of  the  milk,  as  the 
cream  rises.  For  this  purpose  two  quarts  of  milk  were 
taken ;  one  was  milk  obtained  from  a  milkman  and  then 
bottled  and  tested  after  having  stood  four  hours  for  the 
cream  to  rise ;  the  other  was  a  quart  bottled  by  the  milkman 
and  delivered  in  the  usual  way,  the  cream  having  risen. 

The  top  nine  ounces  were  removed  from  each  bottle 
and  tested  for  fat  and  solids  not  fat  (sugar  and  proteids) 
by  the  methods  described  in  the  section  on  milk  testing 
(Chap.  XIV.).  It  was  found  that  there  was  only  a  slight 
falling  off  in  the  quantity  of  proteids  and  sugar  in  the  top 
milks,  as  will  be  seen  in  the  illustration  (Fig.  54). 

It  will  be  noticed  that  the  cream  did  not  separate 
completely  in  the  milk  that  was  obtained  from  the  milk- 
man and  stood  in  the  bottle  but  four  hours.  This  was 
because  it  was  not  bottled  immediately  after  milking. 
Cream  rises  quite  completely  in  four  hours  if  the  milk  is 
bottled  shortly  after  milking,  but  not  otherwise. 

From  these  illustrations  it  will  be  seen  that  it  is  hope- 
less to  expect  any  degree  of  accuracy  in  making  up  food 
mixtures  of  milk  and  cream  unless  each  is  assayed,  or 
to  have  the  food  uniform  from  day  to  day;  but  if  definite 
quantities  are  removed  from  the  top  of  a  quart  bottle  of 
milk  after  the  cream  has  risen,  nearly  the  same  composi- 
tion will  be  obtained  each  day,  as  a  milkman's  milk  usu- 


220 


INFANT   FEEDING. 


all}'  is  quite  uniform  from  day  to  day,  and  the  strength  of 
the  food  can  be  varied  with  the  greatest  ease  by  increasing 
or  decreasing  the  dilution  of  the  top  milk.  Any  desired 
proportion  between  fat  and  proteids  can  be  had  by  taking 


^ 


BOTTLED 
4  HOURS 

FIRST  TEST 

FAT  IN  WHOLE  MILK 
3At 


TOP  9  OZS. 
.REMOVED  AND  MIXED 
}-         CONTAINED 
FAT  8^ 

SOLIDS  NOT  FAT  6.6^ 


REMAINING  MILK 

OR  SKIM  MILK 

CONTAINED 

FAT  1.6^ 

SOLIDS  NOT  FAT  7.17;1 


BOTTLED 
18  HOURS 

SECOND  TEST 

FAT  IN  WHOLE  MILK 


TOP  9  OZS. 
REMOVED  AND  MIXED 

CONTAINED 
FAT  14  f. 

SOLIDS  NOT  FAT  8.5^ 


REMAINING  MILK 

OR  SKIM  MILK 

CONTAINED 

FAT  .8?6 

SOLIDS  NOT  FAT  8.76^ 


Fig.  54.  —Showing  Solids  not  Fat  in  Top  Milk  and  Remaining-  Milk. 

a  greater  or  less  quantity  from  the  bottle.  By  varying  the 
richness  of  the  top  milk  in  cream,  and  the  dilution,  the 
composition  of  the  food  can  be  varied  to  suit  the  infant's 
digestion.  It  should  be  remembered  that  percentages 
should  be  calculated  after  something  that  agrees  with  the 


PREPARING    INFANT'S    FOOD. 


221 


infant  has  been  found ;  it  is  then  time  to  see  if  the  food 
contains  enough  proper  nourishment.  This  method  al- 
lows the  greatest  variation  in  composition  of  food  without 
any  calculation,  and  when  a  food  that  suits  the  infant's 
digestion  is  found  its  composition  can  be  known  within  a 
slight  fraction,  especially  the  protein,  which  is  of  such 
importance. 

These  top  milks  should  be  looked  upon  as  concen- 
trated milks  that  require  dilution  to  suit  the  infant's  diges- 
tion. Of  course  sugar  must  be  added.  About  five  or  six 
per  cent  is  the  usual  quantity  required.  This  would  be 
about  one  ounce  of  sugar  to  twenty  ounces  of  food,  or 
one-twentieth  of  any  mixture  (128). 

An  easy  way  of  bringing  to  mind  the  percentages  ob- 
tained by  various  layers  of  milk  may  be  acquired  by  tabu- 
lating the  ingredients  of  9  and   16  ounce  top  milk.     It  is 


Fat. 
Per  cent. 

Proteids. 
Per  cent. 

15 

4 

9 

4 

12 

s 

4 
4 

9 
6 

3 
3 

Sugar. 
Per  cent. 


Very  rich  milk.  Butter  fat,  five 
per  cent.      High  grade,  blooded 

Guernseys  and  Jerseys 

Rich  milk.  Butter  fat,  four  per 
cent.  Ordinary  Guernseys  and 
Jerseys 

Thin  milk.  Butter  fat,  three  per 
cent.  Holstein  and  ordinary 
milk  cows 


f  Top    g  ounces. 
i  Top  16  ounces. 

/  Top     g  ounces. 
[  Top  16  ounces. 

f  Top    g  ounces. 
I  Top  16  ounces. 


based  upon  the  fact  that  the  proteids  in  whole  milk  equal 
the  fats  up  to  4  per  cent.  In  actual  practice  milk  varying 
from  3  to  5  per  cent  butter  fat  will  be  met.  If  the  milk 
contains  3  per  cent  fat,  it  will  have  about  3  per  cent  pro- 
teids; 4  per  cent  fat,  4  per  cent  proteids,  but  5  per  cent 
fat  in  milk  is  accompanied  by  only  about  4  per  cent  pro- 


222  INFANT    FEEDING. 

teids.  While  the  butter  fat  in  milk  can  be  determined 
only  by  assay  (75),  certain  grades  of  cows  give  a  fairly 
uniform  milk  in  this  respect. 

It  will  be  noticed  that  the  top  9  ounces  give  a  ratio  of 
fats  to  proteids  of  3  to  1,  and  the  top  16  ounces  a  ratio  of 
2  to  1,  whether  the  milk  is  rich  or  thin.  Hence  practically 
the  same  percentages  will  be  obtained  by  this  method  no 
matter  what  kind  of  milk  is  used.  Rich  milk  will  be 
diluted  more  and  poor  milk  less  to  preserve  the  proper 
proportions.  It  is  thus  merely  a  matter  of  dilution,  when 
we  know  the  general  strength  of  the  whole  milk.  To  find 
the  percentages  actually  given  to  the  baby,  divide  any  of 
the  above  figures  by  the  dilution.  Thus,  one  part  of  top 
milk  to  three  parts  of  diluent  will  give  a  dilution  of  4. 

Kxample :  9  oz.  Top  muic.  16  oz.  top  muic. 

Fat.        Proteids.     Sugar.  Fat.       Proteids.     Sugar. 

Very  rich  milk a  )jL5 4 4  4)^ 4 4 

3H         ~    ~ "i  2X  i  I 

Rich  milk 4)J^ 4 4  4)_S 4 4 

311  2  11 

To  get  about  the  same  percentages  from  thin  milk 
use  one  part  of  top  milk  to  two  parts  of  dilutent,  giving  a 
dilution  of  3. 

Fat.       Proteids.     Sugar.                          Fat.      Proteids.     Sugar. 
Thin  milk 3)9  4 4_  3)6 3 4 

3  i  ilA  2  i  t-Vs 

We  can  thus,  by  varying  the  dilution  in  a  sliding  scale, 
get  a  wide  variation  in  percentages.  In  cases  of  indiges- 
tion it  is  simply  a  question  of  dilution,  according  to 
whether  the  fats  or  proteids  are  disagreeing.  If  we  wish 
to  rundown  the  fats,  dilute  a  thin  top  milk,  or  even  whole 
milk.     If  we  wish  to  keep  the  fats  high,  dilute  a  rich  top 


PREPARING  INFANT'S   FOOD. 


^^5 


milk.  A  glance  at  the  table  will  suggest  many  possible 
variations.  The  proper  strength  of  the  food  must  depend 
upon  the  digestive  power  as  shown  by  the  stools.  In 
diluting  cow's  milk,  the  top  pint  of  a  quart  of  milk  when 
creaming  has  taken  place,  even  if  simply  poured  off,  con- 
tains a  ratio  of  fats  to  proteids  of  about  2  to  i.  In  dilut- 
ing whole  cow's  milk,  it  is  only  necessary  to  remember 
that  the  fats  and  proteids  are  about  equal  in  thin  and 
moderately  rich  milk,  the  former  containing  fats  and  pro- 
teids 3  per  cent,  the  latter  fats  and  proteids  4  per  cent. 
Both  grades  contain  sugar  about  4  per  cent. 

133.  Diluents. — There  has  been  a  great  deal  of  discus- 
sion as  to  what  diluent  should  be  used.  Jacobi  has  advo- 
cated for  years  the  use  of  cereal  waters  on  account  of  their 
rendering  the  curds  of  cow's  milk  softer;  objection  has 
been  raised  to  this  method  on  the  ground  that  nature  was 
not  being  followed,  as  no  human  breast  secreted  cereals. 
This  argument  is  offset  by  the  fact  that  no  human  breast 
has  been  known  to  secrete  cow's  milk,  which  was  intended 
for  so  different  a  digestive  tract  (Chaps.  IV.,  VIII.). 

No  diluent  has  been  proposed  that  does  not  have  some 
effect  on  the  curding  of  cow's  milk.  There  is  no  denial  of 
the  efficacy  of  the  cereal  waters,  but  their  opponents  claim 
that  they  get  as  good  results  with  plain  water  in  most 
cases.  It  will  be  noticed  that  lime  water  is  always  to  be 
added  when  plain  water  is  used.  This  is  stated  to  be  for 
the  purpose  of  rendering  the  milk  alkaline.  The  dis- 
covery that  fresh  milk  is  not  really  acid  (37)  and  the 
fact  that  less  than  four  parts  of  lime  to  ten  thousand  parts 
of  milk  will  cause  the  mucoid  proteid  of  the  milk  to  swell 
up  and  become  viscid  (45),  thus  tending  to  gelatinize  the 


224  INFANT   FEEDING. 

curd,  and  by  its  alkaline  reaction  to  retard  the  action  of 
rennet,  shows  that  this  method  of  diluting  milk  has  an 
effect  on  its  curding ;  so  the  great  difference  is  whether 
the  process  to  be  used  shall  be  mechanical  or  chemical. 
If  the  milk  has  begun  to  develop  true  acidity  (37),  of 
course  some  alkali  is  needed.  Lime  or  bicarbonate  of 
soda  is  equally  good  for  this  purpose,  but  the  bicarbon- 
ate of  soda  does  not  cause  the  milk  to  become  so  thick 
and  viscid  as  the  lime. 

Owing  to  the  character  of  the  curd  of  cow's  milk  it  is 
seldom  that  young  infants  can  take  the  quantity  of  protein 
that  the  breast-fed  infant  receives,  which  largely  accounts 
for  the  well-known  greater  mortality  of  bottle-fed  infants. 
It  may  be  months  before  the  bottle  baby  receives  half  as 
much  cell-building  material  as  the  breast-fed.  For  this 
reason  and  others  to  be  mentioned  in  another  place  (158) 
the  author  believes  that  the  best  general  diluent  for  cow's 
milk  is  a  cereal  gruel  in  which  the  starch  has  been  dex- 
trinized  or  rendered  soluble  by  the  action  of  diastase. 
This  gruel,  which  may  be  made  from  any  cereal,  renders 
the  curds  of  cow's  milk  more  flocculent,  and  also  increases 
the  quantity  of  tissue-building  protein  the  infant  receives 
and  digests,  oftentimes  by  fifty  to  one  hundred  per  cent, 
which  is  of  great  value.  In  the  milks  of  all  animals  there 
is  more  or  less  soluble  nutriment  that  can  be  absorbed 
without  digestive  effort,  and  particularly  so  in  woman's 
milk.  Diluting  cow's  milk,  which  contains  less  soluble 
nutriment  than  woman's  milk,  reduces  the  quickly  absorb- 
able part  of  the  food  to  almost  nothing.  This  is  partially 
replaced  by  the  digested  starch  of  dextrinized  gruels,  which 
is  easily  absorbed  and  assimilated.     The  youngest  infant 


PREPARING   INFANT'S   FOOD.  225 

can  usually  assimilate  these  gruels,  in  fact  in  many  cases 
there  is  no  other  form  of  nourishment  so  well  borne. 
The  advantages  of  this  form  of  diluent  are:  (1)  It  acts 
mechanically  on  curds;  (2)  it  furnishes  tissue-building 
proteid  in  appreciable  amount ;  (3)  it  forms  the  best  tem- 
porary substitute  for  milk ;  (4)  it  is  always  at  hand  when 
wanted;  and  (5)  it  can  be  easily  and  cheaply  prepared  (17). 

At  the  Pan-American  Medical  Congress  of  1893  the  au- 
thor proposed  a  method  of  preparing  these  gruels,  which, 
however,  proved  to  be  too  complicated  for  general  use. 
Since  then  an  easier  process  has  been  worked  out  (137). 

A  simple  decoction  of  diastase  for  dextrinizing  gruels 
may  be  made  as  follows : 

A  tablespoonful  of  malted  barley  grains  crushed  is  put 
in  a  cup  and  enough  cold  water  added  to  cover  it,  usually 
two  tablespoonfuls,  as  the  malt  quickly  absorbs  some  of 
the  water.  This  is  prepared  in  the  evening  and  placed  in 
the  refrigerator  over  night.  In  the  morning  the  water, 
looking  like  thin  tea,  is  removed  by  a  spoon  or  strained 
off,  and  is  ready  for  use.  About  a  tablespoonful  of  this 
solution  can  be  thus  secured  and  is  very  active  in  diastase. 
It  is  sufficient  to  dextrinizeapint  of  gruel  in  ten  or  fifteen 
minutes.  Such  a  decoction  must  be  prepared  each  day 
as  it  soon  spoils,  owing  to  the  unstable  nature  of  the 
enzyme  (11).  For  this  reason  it  may  be  more  convenient 
to  use  some  commercial  preparation  of  diastase.  Of  the 
many  in  the  market  the  author  uses  and  prefers  a  glycerite 
of  diastase  known  as  Cereo,  which  is  specially  made  for 
dextrinizing  gruels.  This  retains  its  activity  indefinitely 
and  under  varying  temperatures  owing  to  the  menstruum 
employed. 


226  INFANT   FEEDING. 

134.  There  are  a  certain  number  of  cases  that  every 
physician  meets  in  which  cow's  milk,  even  in  the  highest 
dilution,  will  not  be  tolerated  temporarily.  To  some  this 
is  a  source  of  mortification,  especially  when  the  mother 
tries  some  proprietary  food  with  a  prompt  gain  in  weight 
as  a  result,  after  the  doctor's  efforts  with  cow's  milk  have 
failed.  The  trouble  here  is,  the  doctor  has  been  trying  to 
make  the  baby  conform  to  his  theory  of  what  it  ought  to 
take  instead  of  trying  to  find  what  it  could  take,  and  then 
adjusting  the  food  as  rapidly  as  possible  so  that  it  would 
contain  enough  protein  to  build  cells,  and  enough  fat  and 
carbohydrates  to  produce  heat  and  energy. 

In  this  class  of  cases  condensed  milk  is  often  the  best 
thing  to  start  with,  after  being  modified  as  described  in 
the  following  chapters.  The  great  objection  to  condensed' 
milk  is  not  that  it  is  condensed,  but  that  the  food  ele- 
ments are  out  of  proportion. 

135.  In  many  cases  in  which  the  appetite  is  poor  or 
digestion  very  weak,  food  is  required  that  stimulates  the 
appetite  and  flow  of  digestive  juices,  or  that  can  be 
•absorbed  with  little  digestive  effort.  It  is  here  that  beef 
juice,  scraped  beef,  broths,  peptonized  milk,  whey,  eggs, 
and  gruels  find  their  usefulness. 


CHAPTER   XXII. 

PREPARATION   OF   FOOD. 

Top  Milk  Mixtures  —  Pasteurization  —  Percentage 
Composition — Whey  and  Cream  Mixtures — Whey 
— Peptonized  Milk— Scraped  Beef — Beef  Juice — 
Beef  Tea — Meat  Broths — Egg  Mixtures — Milk 
Laboratories. 

In  the  previous  chapters  the  character  of  the  food 
required  to  develop  the  tissues  and  organs  has  been  de- 
scribed and  the  method  of  securing  the  raw  materials. 
In  this  chapter  will  be  given  the  methods  of  preparing 
them  for  use  of  the  infant  under  different  conditions. 

Top  Milk  Mixtures. 

136.  Top  Milk. — Use  the  mixed  milk  of  a  herd  of  cows. 
Have  it  bottled  and  cooled  as  soon  as  possible  after  milk- 
ing. "Certified  Milk"  (68)  should  be  obtained  when 
possible.  When  such  milk  is  delivered  the  layer  of  cream 
will  be  distinct  in  the  neck  of  the  bottle. 

For  young  infants,  remove  from  the  top  of  a  quart 
bottle  all  the  cream  and  enough  milk  to  make  nine  ounces, 
and  mix  in  a  pitcher  or  bowl  for  dilution.  This  is  called 
nine-ounce  top  milk.     (Fat  to  proteids,  3:1.) 

For  older  infants,  remove  from  the  top  of  a  quart  bottle 
all  the  cream  and  enough  milk  to  make  sixteen  ounces 
(one  pint)  and  mix  in  a  pitcher  or  bowl  for  dilution.  This 
is  called  sixteen  ounces  top  milk.     (Fat  to  proteids,  2:1.) 


228 


INFANT   FEEDING. 


The  top  milk  can  easily  be  removed  by  using  the  au- 
thor's dipper  *  shown  in  the  illustration.  The  first  dip- 
perful  must  be  removed  with  a  teaspoon,  as  inserting  the 
dipper  into  the  full  bottle  will  cause  it  to  overflow.     If  a 


FOR  9  OZ. 

2nd0Z  V  T0P  M,LK 
>  REMOVE 
THIS 
QUANTITY 
AND  MIX 


1  OZ 
)IPPEF 


|  FOR  REMOVING 

TOP  MILK 

I5T0Z.  MUST 

BE  REMOVED 

WITH 
A  TEASPOON 


Figs.  55  and  56. — Quart  Bottle  of  Milk  Ready  for  Use,  with  Dipper. 


siphon  is  used  to  remove  the  milk  from  under  the  cream, 
the  sediment — there  is  always  some — goes  into  the  infant's 
food,  and  the  manipulation  is  rather  difficult. 

*  These  dippers  may  be  made  by  any  instrument  maker  and  are  inexpensive 
to  produce. 


PREPARATION    OF   FOOD.  229 

Since  the  introduction  of  this  dipper  in  1899  many 
have  suggested  that  the  bottom  would  push  the  cream 
down  into  the  milk.  This  seems  plausible,  but  a  great 
many  assays  of  the  milk  after  the  cream  has  been  re- 
moved show  that  this  is  not  the  case. 

137-  Diluents :  Sugar  Water,  Plain  Cereal  Gruel,  or 
Dextrinized  Gruel.  Beat  up  one  to  two  heaping  table- 
spoonfuls  of  barley,  wheat,  or  rice  flour  with  enough  cold 
water  to  make  a  thin  paste ;  or  use  two  to  four  heaping 
tablespoonfuls  of  rolled  oats.  Pour  on  a  quart  of  boiling 
water  and  boiliox  at  least  fifteen  minutes,  preferably  in  a 
covered  double  boiler  as  the  gruel  will  not  then  burn.  If 
the  mixture  is  to  be  dextrinized  after  it  is  cooked,  place  the 
cooker  in  cold  water,  and  when  the  gruel  is  cool  enough  to 
be  tasted  add  one  teaspoonful  of  diastase  solution,  or 
Cereo,  and  stir  (133).  This  will  thin  the  gruel.  Strain, 
add  salt  to  taste,  and  cool. 

Wheat,  barley,  and  rice  are  well  absorbed  and  should 
be  used  when  the  bowels  move  naturally.  Oatmeal  con- 
tains considerable  coarse  material  that  stimulates  the 
bowels,  and  should  be  used  when  the  bowels  are  con- 
stipated. 

138.  Sugar  is  not  added  to  sweeten  the  food,  but  to 
supply  heat-producing  food.  The  dipper  holds  one  ounce 
of  granulated  sugar;  two  level  tablespoonfuls  also  equal 
one  ounce.  Three  level  tablespoonfuls  of  milk  sugar 
equal  one  ounce.     Either  may  be  used. 

Preparation  of  Food. 

139.  Before  attempting  to  prepare  the  food  dip  a  strip 
of  blue  litmus  test  paper  into  the  top  milk.     If  the  color 


230  INFANT    FEEDING. 

is  only  slightly  changed  the  milk  is  fresh.  If  the  color  is 
changed  to  dull  red,  the  milk  is  beginning  to  sour.  It 
will  be  bright  red  if  the  milk  is  quite  acid. 

For  Young  Infants. — One  part  of  the  nine-ounce  top 
milk  should  be  mixed  with  3  to  8  parts  of  the  diluent,  and 
1  part  of  sugar  added  to  20  to  30  parts  of  food ;  granulated 
or  milk  sugar  may  be  used. 

For  Older  Infants. — One  part  of  the  sixteen-ounce  top 
milk  should  be  mixed  with  1  to  2  parts  of  the  diluent,  and 
1  part  of  sugar  added  to  20  to  30  parts  of  food ;  granulated 
or  milk  sugar  may  be  used. 

In  every  instance  begin  on  a  weak  mixture  and  gradu- 
ally decrease  the  dilution. 

Any  quantity  may  be  mixed,  from  about  two  ounces 
up  to  enough  for  twenty-four  hours. 

In  making  up  a  small  quantity  a  teaspoon,  dessert- 
spoon, tablespoon,  or  the  dipper  may  be  used  as  a  measure. 

Example  :  Mixture  about  2  ounces  one-fifth  top  milk. 
2  teaspoonfuls  of  9  ounce  top  milk  (after  being  removed  from  bottle  and 

mixed). 
8  teaspoonfuls  of  diluent. 

10  teaspoonfuls  ;  add  one-twentieth  sugar,  or  one-half  teaspoonful. 

When  the  dipper  is  used,  greater  accuracy  in  quantity 
will  be  obtained  and  the  result  will  be  a  definite  number 
of  ounces  which  is  not  the  case  when  a  teaspoon  or  table- 
spoon is  used,  as  these  vary  in  size.  This  does  not  affect 
the  strength  of  the  mixture,  however. 

Example  :  Mixture  12  ounces  one-third  top  milk. 

4  dipperfuls  (4  ounces)  16-ounce  top  milk  (after  being  removed  from 

bottle  and  mixed) . 

5  dipperfuls  (8  ounces)  diluent. 

12  dipperfuls  (12  ounces) ;  add  one-twentieth  of  sugar,  or  one-half  ounce. 


PREPARATION    OF    FOOD.  231 

A  quart  graduate  may  be  used  in  making  up  enough  for 
all  day ;  all  that  is  necessary  is  to  know  how  many  ounces 
of  the  top  milk,  diluent,  and  sugar  are  to  be  mixed.  It 
is  easy  to  remember  that  one  part  of  sugar  is  to  be  added 
to  twenty  to  thirty  parts  of  food,  and  that  two  level  table- 
spoonfuls  of  granulated  or  three  level  tablespoonfuls  of 
milk  sugar  equal  one  ounce. 

The  following  mixtures  illustrate  the  simplicity  of 
preparing  food  by  this  method  and  are  about  the  quan- 
tities and  dilutions  that  will  be  needed  for  the  great  ma- 
jority of  cases ;  each  can  be  prepared  from  one  quart  of 
milk.  In  feeding  it  is  best  to  begin  with  a  weak  mixture 
and  increase  the  strength  as  fast  as  the  infant's  digestion 
will  permit. 


Progressive  Increase  of  Quantity  and  Strength  of 
Mixtures. 

r  ...  ...  f  2  °zs-  of  9  oz.  top  milk  (after  being  re- 

16  ounces — one-eighth  top  milk. ... .    1  ,,        ,       .         ,..■■. 

.   °             r  moved  from  bottle  and  mixed). 

Eight    2-oz.     feedings  ;      one   every    two  -,  ,   ... 

,                               &                          J  14  ozs.  of  diluent, 

hours.  r              „ 

[  1  oz.  of  sugar.  * 

(3  ozs.  of  9  oz.    top   milk   (after  being 
21  ounces — one-seventh  top  milk 1  ,  ,        ,      ,         ,     .     -, 

removed  from  bottle  and  mixed, 
tight    2%-oz.    feedings  ;  one   every   two  <     „  r   ... 

,  18  ozs.  of  diluent. 

hours.  .  „ 

I   1  oz.  of  sugar. 

.    ,,    .  ...  f  4  ozs.  of  9  oz.  top  milk  (after  being  re- 

24  ounces— one-sixth  top  milk ,c        ,      ,       \     .     , 

„.  ,.  moved  from  bottle  and  mixed), 

r-ignt  3-ounce   feedings  ;  one  every   two  - 

&  '20  ozs.  diluent, 

hours.  I  -  „ 

I    1  oz.  sugar.  - 

-f.,    ....  f  °  ozs.  of  goz.  top  milk  (after  being  re- 

30  ounces— one-fifth  top  milk .,        L     ,         ,     . 

„  .     ,.  moved  from  bottle  and  mixed) . 

beven  4-oz.  feedings  ;  one  every  two  and  -  -  ... 

,    . ,  J  24  ozs.  of  diluent, 

a  half  to  three  hours.  , 

I  \yz  ozs.  of  sugar. 

36  ounces— one-fourth  top  milk p  ozs.  of  top  milk  from  one-quart  bottle. 

Six  6-oz.  feedings  ;  one  every  three  hours.  )  27  ozs.  of  diluent. 

'  i}4  ozs.  of  sugar.* 

*  See  Note  on  page  232. 


232  INFANT   FEEDING. 

(14    ozs.   of  top    milk    from    one-quart 

42  ounces — one-third  top  milk I       bottle. 

Six  7-oz.  feedings  ;  one  every  three  hours.   I  28  ozs.  of  diluent. 

I   2  ozs.  of  sugar.* 

,     1f,           .,,  f  20  ozs.  of   top   milk    from   one-quart 

40  ounces — one-half  top  milk ^  ^ 

o-  c        a  c    a-  bottle, 

bix    7-oz.    or    five    8-oz.    feedings  ;     one  J 

..  ..  ,      ,    ,,  ,  !   20  ozs.  of  diluent, 

every  three  to  three  and  a  halt  hours. 

I   1  oz.  of  sugar. :: 

48  ounces — two-thirds  top  milk t  .    c     .„ 

n  r  1  quart  ol  milk. 

Six   8-oz.    or   five    10-oz.   feedings  ;    one  <         ■   .     c  ,■, 

&    '  1  pint  of  diluent. 

every  three  and  a  half  hours.  \ 

140.  After  the  food  has  been  prepared  it  should  be 
placed  in  separate  nursing  bottles  and. these  plugged  with 


Fig.  57. — Nursing  Bottle. 


58.  —  Nursing  Bottle, 
Preferable. 


Fig.  59. —  Funnel  for  Filling 
Bottles. 


clean  cotton  and  kept  on  ice  or  in  a  refrigerator  away  from 
meat  or  vegetables,  where  the  temperature  is  below  500  F. 
The  temperature  of  many  refrigerators  is  above  6o°  F.  and 
the  milk  should  then  be  put  in  the  ice  receptacle.  When 
the  temperature  of  the  food  is  likely  to  rise  above  6o°  F., 
it  is  best  to  pasteurize  the  food — heat  to  155  to  1650  F. 
The  Freeman  pasteurizer  or  Arnold  sterilizer  may  be 

*  Two  level  tablespoonfuls  of  granulated  sugar  or  three  of  milk  sugar  equal 
about  one  ounce.  Granulated  sugar  may  produce  an  acid  gastric  secretion,  so  it 
is  often  necessary  to  reduce  it  a  little  in  quantity. 


PREPARATION    OF   FOOD. 


233 


Fig.  60. — -Freeman  Pasteurizer. 


used  for  this  purpose ;  or  a  pasteurizer  may  be  made  from 
a  six-quart  tin  pail.     A  false  bottom  is  made  by  punching 

holes  in  a  tin  pie  plate,  which  is 
to  be  inverted  in  the  pail;  this 
prevents  the  bottom  of  the  bot- 
tles getting  too  hot.  It  is  best 
to  have  a  thermometer  pass  in- 
to the  water  through  a  cork  fit- 
ted in  a  hole  in  the  cover. 

The  bottles  are  placed  in 
water  up  to  the  level  of  the  milk 
and  the  water  is  heated  up  to  1650  F.  The  pail  is  then 
removed  from  the  heat  and  covered  with  a  cloth  and  al- 
lowed to  stand  for  half  an  hour.  Where  a  thermometer 
cannot  be  had,  the  water  should  be  brought  nearly  to  the 
boiling  point  before  being  removed  from  the  heat.  The 
bottles  are  then  cooled  by  first  being  placed  in  luke-warm 
water  and  then  in  cold  water.  Pasteurized  milk  should 
be  kept  below  6o°  F.,  or  the  spores  in  the  milk  will  develop 
into  active  bacteria  (48).  A  simple  and  practical  method 
of  keeping 
nursing  bot- 
tles cool,  sug- 
gested by  De 
Forest,  is  to 
place  cracked 
ice  around 
them  in  the 
pasteurizer; 
this  saves  possible  infection  from  food  in  a  refrigerator. 
A  quart  bottle  of  milk  may  be  pasteurized  without  dis- 


Fig.  61.— Arnold  Sterilizer. 


234 


INFANT   FEEDING. 


turbing  the  cream  by  setting  it  in  a  kettle  or  pail  and 
heating  as  just  described. 

Sterilizing  (heating  to  21 2°  F.)  is  not  employed  so 
much  as  formerly,  as  the  taste  of  the  milk  is  greatly 
altered  and  certain  chemical  changes  are  also  produced. 
There  are  no  corresponding  advantages  that  offset  these 
objections  (61). 


Fig.  62.  — Home-made  Pasteurizer. 
(Russell.) 


Fig.  63. — Pasteurizer  for  Bottled  Milk. 
(Russell.) 


When  conditions  are  such  that  pasteurization  as  de- 
scribed cannot  be  carried  out,  the  milk  may  be  brought  to 
a  boil,  preferably  in  a  double  boiler,  and  then  covered  and 
allowed  to  stand  for  twenty  minutes  and  then  cooled. 

141.  Lime  water  added  to  the  food  often  proves  bene- 
ficial, especially  when  there  is  vomiting  or  when  the  milk 
is  slightly  acid  to  litmus  paper.  It  may  be  obtained  at  a 
drug  store  or  readily  prepared  at  home  as  follows :  Get  a 
lump  of  lime  at  a  grocery  store.  Pour  on  a  quart  of  water 
in  an  open  vessel  and  allow  it  to  slake.  When  this  proc- 
ess is  completed  and  the  lime  has  settled,  pour  off  the 


PREPARATION    OF    FOOD. 


235 


clear  liquor  at  the  top,  as  this  contains  the  potash  and 
soda  and  other  soluble  impurities  in  the  lime.  Stir  up 
the  lime  with  another  quart  of  water  and  pour  off  as  be- 
fore; this  will  leave  the  lime  quite  pure.  The  lime  may 
then  be  placed  in  a  large  bottle  or  quart  fruit  jar  and  this 
filled  with  water.  When  the  lime  water  is  clear  it  may 
be  poured  off  into  any  convenient  bottle  for  use,  and 
more  water  poured  on  the  lime.  This  may  be  repeated 
as  long  as  any  lime  remains  undissolved. 

142.  Syrup  of  lime  is  about  thirty  times  as  strong  as 
lime  water  and  can  be  had  at  any  drug  store.  Where  it 
is  not  convenient  to  obtain  or  make  the  lime  water,  one 
ounce  of  syrup  of  lime  may  be  added  to  a  quart  of  boiled 
water  or  one  teaspoonful  to  four  ounces.  It  may  also  be 
added  directly  to  the  feedings,  about  one  or  two  drops  to 
a  bottle. 

Composition  of  Mixtures. 

143.  It  is  impossible  to  tell  the  exact  composition  of 
mixtures,  as  that  will  depend  on  the  richness  of  the  orig- 
inal milk,  but  the  range  of  composition  will  always  fall 
within  the  following  limits,  without  the  solids  of  the 
diluent  and  the  sugar. 


Lowest  Extreme. 

Highest  Extreme. 

9  oz.  Top  Milk. 

9  oz.  Top  Milk  from  Milk  Three 
Per  Cent.  Fat. 

9  oz.  Top  Milk   from   Milk   Five 
Per  Cent.  Fat. 

Fat. 
Per  cent. 

Proteids. 
Per  cent. 

Sugar. 
Per  cent. 

Fat. 
Per  cent. 

Proteids. 
Per  cent. 

O.50 

Sugar 
Per  cent. 

Diluted  8  times* 

I.  IO 

O.38 

O.50 

2.00 

O.50 

"      7      "     

"      6     "     

"       5      "      

I.30 
I.50 

I.80 

•43 
•SO 
.60 

•57 
.67 
.80 

2.30 
2.67 
3.20 

•57 
.67 
.So 

•  57 
.67 
.80 

4     "      

2.25 

•75 

1. 00 

4.OO 

1. 00 

1. 00 

"      3      "      

3.OO 

1. 00 

i-33 

5.60 

i-33 

1-33 

*  Diluted  8  times  means,  1  part  top  milk,  7  parts  diluent,  etc. 


236 


INFANT   FEEDING. 


Lowest  Extreme. 

Highest  Extreme. 

16  oz.  Top  Milk. 

16  oz.  Top  Milk  from  Milk  Three 
Per  Cent.  Fat. 

16  oz.  Top  Milk  from   Milk  Five 
Per  Cent.  Fat. 

Fat. 
Per  cent. 

Proteids. 
Per  cent. 

Sugar. 
Per  cent. 

Fat. 
Per  cent. 

Proteids. 
Per  cent. 

Sugar. 
Per  cent. 

Diluted  3  times* 

0.7 

O.38 

O.50 

I.  12 

O.50 

O.50 

"      6     "      

"       5     "      

.8 

•9 
1. 1 

•43 
•5o 
.60 

•57 
.67 
.80 

I.30 
I.50 
I.  So 

•57 
.67 
.80 

•57 
.67 
.80 

"      4     "      

1.4 

•75 

1.00 

2.25 

1. 00 

1. 00 

1.8 

1. 00 

i-33 

3.OO 

i-33 

i-33 

ti        2       * 4 

2.7 

1.50 

2.00 

4- 50 

2.00 

2.00 

A  dextrinized  gruel  will  contain  from  0.3  to  0.5  per 
cent  proteids,  2  to  4  per  cent  soluble  carbohydrates,  de- 
pending' on  whether  one  or  two  heaping  tablespoonfuls  of 
cereal  flour  is  used  to  the  quart,  which  adds  to  the  nutri- 
tive value  of  the  mixture. 

In  calculating  percentages  of  sugar  the  following 
figures  will  be  found  exact  and  simple : 

One  part  sugar  to  twenty         parts  mixture  adds  five  per  cent. 

"       "        "       "   twenty-five     "  "  "     four 

"       "        "       "  thirty  "  "     three  " 

"       "        "       "  forty  "    two  and  a  half        " 

"       "        "       "   fifty  "  "  "     two  " 

144.  The  principle  of  preparing  food  with  the  dipper 
admits  of  many  applications.  Cragin  has  devised  an  out- 
fit called  the  "  Sloane  Maternity  Milk  Set,"  consisting  of 
a  measuring  glass  graduated  for  twenty  ounces  of  food, 
and  the  author's  dipper.  The  top  milk  is  removed  from 
the  milk  bottle  and  mixed. 


Directions  for  Use. 

Get  a  quart  bottle  of  good  milk  and  let  it  stand  on  ice 
or  in  a  cool  place  for  half  an  hour  so  that  the  cream  will 
show  at  the  top  of  the  bottle. 

"  Diluted  S  times  means,  i  part  top  milk,  7  parts  diluent,  etc. 


PREPARATION    OF    FOOD. 


237 


From  the  upper  part  of  the  bottle  are  obtained  two 
kinds  of  top  milk: 

Top  Milk  No.  /.,  obtained  by  taking  ten  dipperfuls 
from  the  top  of  the  bottle,  the  first  dipper  being  filled  with 
a  spoon  to  prevent  spilling,  the  re- 
maining nine  dipperfuls  being 
taken  by  dipping  carefully  from 
the  bottle.  These  ten  dipperfuls 
are  to  be  mixed  in  a  clean  pitcher, 
and  from  the  milk  thus  mixed  the 
baby's  food  may  be  prepared  until 
it  is  from  four  to  six  months  old. 

Top  Milk  No.  II,  obtained  by 
taking  sixteen  dipperfuls  from  the 
top  of  the  bottle,  the  first  dipper 
being  filled  as  before  with  a  spoon, 

the  remaining  fifteen  dipperfuls  being  taken  by  dipping 
carefully  from  the  bottle. 

These  sixteen  dipperfuls  are  to  be  mixed  in  a  clean 
pitcher  and  from  the  milk  thus  mixed  the  baby's  food 
may  be  prepared  from  the  age  of  about  four  months  until 
it  is  a  year  old. 

In  using  this  milk  set,  whatever  strength  of  food  is 
desired,  the  sugar  and  the  lime  water  are  always  the  same : 
one  ounce  of  milk  sugar  (or  one-half  ounce  of  granulated 
sugar)  and  one  ounce  (one  dipperful)  of  lime  water. 

The  quantity  of  food  made  by  filling  the  glass  once  is 
always  the  same — twenty  ounces.  The  strength  of  the 
food  varies  with  the  number  of  dipperfuls  of  top  milk  used. 


Fu;.  64. — Sloane  Maternity  Milk  Set. 


238  INFANT   FEEDING. 

Preparation  of  the  Food. 

First.  Into  the  measuring  glass  pour  milk  sugar  up  to 
the  line  marked  one  ounce  milk  sugar,  or  granulated  sugar 
up  to  the  line  marked  one-half  ounce  granulated  sugar. 

Second.  Add  one  dipperful  of  lime  water  and  mix  by 
shaking  the  glass. 

Third.  Add  the  required  number  of  dipperfuls  of  top 
milk  according  to  the  age  of  the  baby  as  explained  below. 

Fourth.  Fill  the  measuring  glass  up  to  the  line  marked 
twenty  ounces  of  food,  with  water,  either  plain,  or  barley 
water,  or  oatmeal  water. 

During  the  first  month  it  is  usually  better  to  use  plain 
water,  after  that  barley  water,  or  if  the  baby  is  very  con- 
stipated oatmeal  water. 

Strength  of  Food  for  Different  Months. 

First  day — Give  no  milk;  put  in  milk  sugar  to  mark, 
then  fill  with  boiled  water. 

Second  day — Add  one  dipperful  of  top  milk  No.  I. 

Third  day — Add  two  dipperfuls  of  top  milk  No.  I. 

Fourth  day — Add  three  dipperfuls  of  top  milk  No.  I. 

Fifth  to  tenth  day — Add  four  dipperfuls  of  top  milk 
No.  I. 

Tenth  to  thirtieth  day— Add  five  dipperfuls  of  top 
milk  No.  I. 

One  month  to  two  months — Add  six  dipperfuls  of  top 
milk  No.  I. 

Two  months  to  four  months — Add  seven  dipperfuls 
of  top  milk  No.  I. 

Four  months  to  nine  months — Add  ten  dipperfuls  of 
top  milk  No.  II. 


PREPARATION    OF    FOOD.  239 

When  the  baby  needs  more  than  twenty  ounces  in  the 
twenty-four  hours,  fill  the  measuring  glass  twice  instead 
of  once,  before  putting  the  food  into  the  baby's  bottle. 

After  nine  months  the  food  is  prepared  by  shaking 
the  quart  bottle  of  milk  when  first  obtained  and  using  the 
plain  mixed  milk. 

After  preparing  the  food  put  it  (especially  in  hot 
weather)  on  the  stove  and  heat  it  till  it  simmers.  It  is 
then  ready  to  be  placed  in  the  baby's  bottles  which  have 
been  thoroughly  washed  in  hot  soapsuds  and  rinsed. 

The  above  directions  are  given  for  an  average  healthy 
baby.  A  frail  baby  or  one  whose  weight  is  below  the 
average  will  need  to  have  the  strength  of  food  increased 
more  slowly.  A  very  strong,  healthy  baby  may  have  the 
strength  of  the  food  increased  more  rapidly.  If  the 
stronger  food  does  not  seem  to  agree  with  the  baby,  de- 
crease the  number  of  dipperfuls  of  milk  used. 

By  increasing  or  decreasing  the  number  of  dipperfuls 
of  milk,  the  food  can  usually  be  adjusted  to  the  child's 
digestion. 

Whey  and  Cream  Mixtures. 

145.  Bartley's  Formula :  *  From  one  quart  of  milk  after 
the  cream  has  risen  siphon  off  the  under  three-fourths 
(this  leaves  the  top  eight  ounces  in  the  bottle).  Place  the 
under  milk  that  was  removed  in  a  double  boiler  and  "  add 
a  teaspoon  and  a  half  of  good  essence  of  pepsin  and  warm 
slowly  to  blood  heat  and  keep  at  that  temperature  until 
thoroughly  curdled.  Now  heat  with  constant  stirring 
until  a  thermometer  dipped  into  the  milk  shows  a  tem- 

*  Brooklyn  Medical  Journal,  May,  1900. 


240  INFANT   FEEDING. 

perature  of  1550  F.  and  remove  from  the  fire;  strain, 
while  hot,  through  a  clean  wire  strainer  and  dissolve  in 
the  whey  a  heaping  tablespoon  of  sugar  of  milk  and  the 
white  of  one  egg.  When  cold  pour  the  sweetened  whey 
back  into  the  milk  bottle  and  mix  thoroughly  with  the 
cream  and  top  milk." 

"  To  reduce  caseinogen  we  draw  off  more  of  the  bottom 
milk.  To  increase  it,  draw  off  less.  To  decrease  fat,  dip 
off  a  part  of  the  cream.  .  .  .  To  increase  the  fat,  add  a  little 
less  than  the  full  amount  of  whey  after  removing  the  curd. 
To  increase  the  soluble  albumins,  add  more  white  of  egg. 
The  sugar  may  be  varied  at  will  by  adding  more  or  less 
as  desired."  The  object  of  heating  the  whey  to  155 °  F.  is 
to  destroy  the  rennet  in  the  essence  of  pepsin  that  causes 
the  milk  to  coagulate.  Otherwise  the  top  milk  would 
curd  when  mixed  with  the  whey. 

Westcott  *  has  published  some  elaborate  formulae  for 
calculating  the  percentages  of  the  fat,  caseinogen,  and 
lactalbumin  in  whey  and  cream  mixtures,  and  a  method 
of  preparing  mixtures.  The  principles  involved  are  prac- 
tically the  same  as  Bartley's,  except  that  no  white  of  egg 
is  used. 

The  original  object  of  the  whey  and  cream  mixtures 
was  to  make  a  substitute  food  that  should  contain  the 
same  protein  ingredients  as  human  milk,  assuming  these 
to  be  definite  proportions  of  caseinogen  and  lactalbumin, 
and  thereby  overcome  the  trouble  caused  by  the  curding 
of  cow's  milk.  The  experiments  of  White  and  Laddt 
led  them  to  report  "  that  whey  has  a  distinct  value  as  a 

*  International  Clinics,  October,  1900.  American  Journal  of  the  Medical 
Sciences,  October,  1901. 

f  Philadelphia  Medical  Journal,  February  2d,  1901. 


PREPARATION    OF    FOOD.  241 

diluent  in  making  the  casein  coagulum  finer,  but  is  in- 
ferior in  this  respect  to  barley  water." 

Since  the  analyses  on  which  these  schemes  of  prepar- 
ing food  are  based  were  published,  much  advanced  work 
with  the  proteids  of  the  milk  of  different  animals  has  been 
done,  and  it  is  now  known  that  the  older  belief  as  to  the 
composition  of  milks  and  the  proportions  between  casein 
and  lactalbumin  has  been  wrong,  especially  in  the  case 
of  woman's  milk  (32). 

In  many  cases  whey  and  cream  mixtures  are  well  borne, 
but  the  proteids  of  whey  do  not  seem  to  have  as  much 
nutritive  value  as  the  proteids  of  the  original  milk  from 
which  it  was  made,  it  having  been  found  in  experiments 
in  feeding  two  hundred  and  fifty-eight  animals  during  an 
extended  period  that  one  part  of  skim  milk  produced  as 
much  gain  in  weight  as  two  parts  of  whey ;  and  slaughter 
tests  showed  the  flesh  of  the  whey-fed  animals  to  be  in- 
ferior to  that  of  those  fed  skim  milk."  The  great  differ- 
ence will  be  seen  by  the  following  approximate  comparison : 


Sugar  and  salts        Total  solids. 


100  c.c.  skim  milk 
200  c.c.  whey 


3.29  gm. 
1.74     " 


5.71  gm.  9.00  gm. 

11.58     "  13.32    " 


Foods  For  Temporarv  Use. 

146.  Whey. — Get  some  junket  tablets  at  any  grocery 
or  drug  store.  Dissolve  one  of  these  in  an  ounce  (two 
tablespoonfuls)  of  cold  water  and  add  this  to  a  quart  of 
fresh  milk.  Warm  gently  until  a  little  above  blood  heat. 
When  the  curd  has  become  quite  solid  beat  up  well  with 

*  Henry  :   "  Feeds  and  Feeding,"  p.  5S6. 
16 


242  INFANT    FEEDING. 

a  fork  and  keep  warm  until  the  curds  have  shrunk  con- 
siderably. Then  strain  off  the  whey  and  set  on  ice. 
Keeping  the  curd  warm  for  ten  or  fifteen  minutes  greatly 
increases  the  yield  of  whey.  Wine  may  be  added  as  a 
flavoring  agent  if  desired. 

147.  Peptonized  Milk.  Warm  Process. — (1)  Empty 
into  a  clean  quart  bottle  the  contents  of  one  of  Fairchild's 
peptonizing  tubes ;  (2)  add  four  ounces  (eight  tablespoon- 
fuls)  of  cold  water;  shake,  and  (3)  add  one  pint  of  cool 
fresh  milk  and^gain  shake;  (4)  place  the  bottle  in  water 
not  too  hot  to  be  uncomfortable  to  the  hand,  for  ten  min- 
utes. Then  either  place  on  ice,  or  boil,  to  prevent  further 
digestive  action.     This  milk  is  likely  to  taste  bitter. 

Cold  Process. — Prepare  the  bottle  as  before,  but  set  on 
ice  without  warming.  This  milk  is  only  partially  pepton- 
ized so  will  not  have  a  bitter  taste. 

148.  Egg  Water.— Beat  up  the  white  of  one  egg  in 
eight  ounces  of  cold  water  and  add  a  pinch  of  salt.  This 
may  be  flavored  with  a  few  drops  of  aromatic  spirits  of 
ammonia  or  of  whiskey. 

Booker*  has  given  the  following  formula:  Egg  water 
is  made  by  beating  the  white  of  egg  in  a  shallow  dish, 
allowing  it  to  stand  for  two  or  three  hours,  then  pour- 
ing off  the  clear  fluid,  leaving  the  foam  behind.  The 
fluid  is  soluble  in  five  parts  of  water.  It  should  be  diluted 
with  a  larger  quantity  of  water  when  the  digestion  is 
feeble,  and  made  palatable  by  the  addition  of  sugar,  salt, 
and  a  few  drops  of  lemon  juice. 

149.    White  of  Egg  and  Dextrinized  Gj'uel. — Add  to 
eight  ounces  of  dextrinized  wheat  flour  gruel  (137)  the 

*  "  Eleventh  Annual  Report  of  the  Thomas  Wilson  Sanatorium  for  Children." 


PREPARATION    OF   FOOD.  243 

white  of  one  fresh  egg,  and  if  well  borne  add  one  to  two 
even  teaspoonfuls  of  granulated  sugar.  Composition  about 
2  per  cent  proteids  and  4  to  7  per  cent  carbohydrates. 

150.  Yolk  of  Egg  and  Dextrinized  Gruel.— Add  to 
eight  ounces  of  dextrinized  wheat  flour  gruel  (*37)  the  yolk 
of  one  fresh  egg  and  if  well  borne  one  to  two  teaspoonfuls 
of  granulated  sugar.  Composition  about  1.5  per  cent 
fat,  1.5  per  cent  proteids,  4  to  7  per  cent  carbohydrates. 
These  egg  mixtures  may  be  heated  up  to  1500  F.  without 
coagulating,  hence  they  may  be  given  warm  if  desired. 

151.  Scraped  Beef  or  Beef  Pulp. — Get  a  piece  of  steak 
perfectly  free  from  taint  or  sliminess,  which  is  caused  by 
bacterial  decomposition  (54) ;  with  a  tablespoon  scrape 
the  meat  until  nothing  but  fibre  remains.  The  pulp  may 
be  salted  and  broiled  slightly,  or  fed  raw  (108). 

152.  Beef  fuice. — 1.  Slightly  broil  a  thick  piece  of  steak 
that  is  free  from  the  slightest  trace  of  taint  or  sliminess; 
cut  in  small  pieces  and  press  in  a  clean  meat  press  or 
lemon  squeezer.  The  yield  of  juice  is  not  large.  2.  Cut 
the  meat  into  small  squares  and  just  cover  with  cold, 
slightly  salted  water,  and  set  on  ice  for  several  hours. 
Then  press  by  squeezing  in  a  piece  of  cheesecloth  (109). 

i53-  Beef  Tea. — -Cut  a  pound  of  lean  meat  into  small 
squares  and  let  stand  in  a  pint  of  cold  water  for  an  hour. 
Heat  to  not  above  1600  F.  and  express  the  meat  through 
cheesecloth.  This  tea  will  contain  considerable  nourish- 
ment. If  heated  higher,  the  proteids  will  coagulate.  If 
the  coagulum  is  fed,  none  of  the  nutritive  value  will  be 
lost;  if  removed,  the  tea  will  simply  have  a  flavor.  The 
nutritive  value  may  be  greatly  increased  by  leaving  some 
of  the  meat  pulp  in  the  tea. 


244 


INFANT   FEEDING. 


-154.  Meat  Broths. — Take  one  pound  of  lean  mutton, 
veal,  or  chicken  with  some  cracked  Ipone  and  cut  into 
small  squares;  add  one  pint  of  cold  water,  heat  gently 
and  allow  to  simmer  for  several  hours;  remove  all  the 
fat.  On  cooling  these  broths  will  gelatinize  (m).  These 
broths,  especially  when  thickened  by  the  addition  of 
flour,  are  highly  nutritive. 

155.  Milk  Laboratories. — The  teachings  of  Rotch 
have  resulted  in  the  establishment  of  the  Walker-Gordon 
laboratories  for  the  preparation  of  infant's  food*  The 
infant's  food  is  put  up  as  a  prescription.  The  physician 
fills  out  the  following  prescription  blank : 

The  Walker-Gordon  Laboratory: 


Per 

:ent. 

Remarks. 

r  Fat 

Number  of 

Milk  sugar 

Albuminoids        .... 

Amount  at 

Total  solids 

Wat*r 

100 

OO 

For  whom  ordered. 

Date, 

Signature, 

If  the  physician  does  not  care  to  mention  the  especial  percentages,  he  can  ask 
for  percentages  which  will  correspond  to  the  analysis  of  average  human  milk,  and 
he  can  then  vary  any  or  all  of  these  percentages  later,  according  to  the  need  of  the 
special  infant  prescribed  for. 

*  These  are  located  in  Baltimore,  Buffalo,  Cincinnati,  Cleveland,  Grand 
Rapids,  Montreal,  New  York,  Ottawa,  Pittsburg,  Providence,  St.  Louis,  Toronto, 
Washington,  D.  C,  and  London,  England. 


PREPARATION   OF   FOOD.  245 

The  attendants  at  the  laboratory  make  up  the  food  by 
mixing  the  quantities  of  centrifugal  cream  (43),  skimmed 
milk,  sugar,  and  water  necessary  to  produce  the  desired 
percentages.  It  sometimes  requires  considerable  experi- 
ence to  know  what  percentages  of  these  ingredients  a 
given  infant  can  digest,  and  often  a  great  deal  of  shifting 
of  percentages  is  necessary  before  the  proportions  that 
agree  are  found.  The  laboratories  stand  ready  to  put  up 
these  and  any  other  food  mixtures  that  may  be  desired. 

Without  a  knowledge  of  dietetics  a  food  laboratory  is 
of  little  value  to  a  physician,  who  must  have  a  knowledge 
of  the  percentages  required  by  various  conditions  to  use 
this  valuable  agent  intelligently.  It  would  be  as  credit- 
able to  send  his  patients  to  a  pharmacy  to  find  out  what 
drugs  they  needed,  as  to  send  them  to  a  food  laboratory 
to  find  what  particular  food  combination  they  should  use. 


CHAPTER    XXIII. 
SELECTION  AND  ADMINISTRATION   OF    FOOD. 

Infant's  Stools — Stomach   Capacity — Care  of 
Nursery  Utensils. 

156.  From  the  time  of  birth  until  the  second  set  of 
teeth  is  supplied  there  is  a  gradual  development  of  the 
digestive  process  and  tract  in  the  following  order  (126) : 

1  st.  The  process  of  absorption. 

2d.  The  production  of  a  stool  and  emptying  of  the 
bowel. 

3.  The  secretion  of  the  digestive  juices. 

4th.  The  development  of  the  stomach  (by  the  curding 
of  the  milk). 

5th.  The  eruption  of  teeth  with  which  to  prepare  solid 
food  for  stomach  digestion. 

Breast  milk  is  the  food  that  was  intended  to  nourish 
the  infant  and  at  the  same  time  promote  this  develop- 
ment. It  is  easy  enough  to  prepare  a  substitute  food  that 
will  contain  as  much  nourishment  as  breast  milk,  but 
often  such  food  causes  digestive  disturbance  or  fails  to 
promote  the  normal  development.  Therefore  substitute 
infant  feeding  calls  for  a  careful  study  of  each  case  to  dis- 
cover if  possible  why  the  substitute  food  is  not  succeed- 
ing. Sometimes  it  will  be  found  that  there  is  a  deficient 
flow  of  digestive  juices ;  in  such  cases  food  that  can  be  ab- 
sorbed with  little  digestive  effort  is  indicated.     At  other 


SELECTION   OF   FOOD.  247 

times  the  intestinal  digestive  juices  will  act,  but  the  stom- 
ach is  at  fault ;  here  food  that  can  easily  leave  the  stom- 
ach is  indicated.     Again,  there  may  be  poor  absorption. 

As  any  food  that  is  not  digested  or  absorbed  will  be 
found  in  the  stools,  an  examination  of  an  infant's  stools 
will  often  show  where  the  trouble  lies,  and  is  absolutely 
necessary  if  intelligent  feeding  is  to  be  done,  as  food  that 
would  be  indicated  with  one  kind  of  stool  might  only 
aggravate  the  trouble  if  fed  to  an  infant  passing  another 
kind.  The  napkins  should  also  be  examined  to  see  if  the 
urine  leaves  any  stain,  as  a  deposit  of  urates  shows  faulty 

metabolism. 

Infant's  Stools. 

The  normal  infant  stool  is  smooth,  yellow,  homoge- 
neous, and  of  about  the  consistency  of  thin  mush.  The 
following  may  be  considered  abnormal  types: 

Curdy  Stools. — Curdy  lumps  may  consist  of  undi- 
gested casein  or  fat.  The  former  are  hard  and  yellowish, 
while  the  latter  are  soft  and  smooth,  like  butter. 

Green  Stools. — Stools  can  be  considered  green  only 
when  that  condition  is  evident  immediately  upon  their 
passage.  They  are  thought  to  be  due  to  a  fermentation, 
which  is  doubtless  the  result  of  bacterial  action.  Certain 
drugs  also  produce  green  stools  (27).  Stools  often  be- 
come green  a  certain  time  after  passage,  caused  by  oxida- 
tion of  the  air. 

Slimy  or  Mucous  Stools. — These  are  the  result  of  ca- 
tarrhal inflammation.  When  the  mucus  is  mixed  with 
the  fecal  matter,  the  irritation  is  high  up  in  the  bowel, 
but  when  flakes  or  masses  of  mucus  are  passed,  the  trou- 
ble is  near  the  outlet. 


248  INFANT   FEEDING. 

Bloody  Stools.— The  appearance  of  these  stools  will 
depend  on  the  portion  of  the  digestive  tract  that  is  affect- 
ed. Small  masses  of  dark  clotted  blood  mixed  in  with 
fecal  matter  indicate  that  the  seat  of  hemorrhage  is  high' 
up,  usually  in  the  small  intestine.  When  bright-red 
blood  is  passed,  the  seat  of  hemorrhage  is  low  down,  usu- 
ally a  little  above  the  anal  ring.  Hard  masses  of  casein 
may  rupture  the  capillaries,  or  a  fissure  or  polyp  may  be 
the  cause  of  the  bleeding.  The  appearance  of  fresh, 
bright-red  blood  in  stools  is  more  alarming  than  danger- 
ous. The  presence  of  dark  clotted  blood  is  of  graver  sig- 
nificance. 

Yellow,  Watery  Stools. — These  are  seen  in  depressed 
nervous  conditions,  especially  in  the  hot  days  of  summer, 
when  the  bowel  is  relaxed  and  the  inhibitory  fibres  of  the 
splanchnic  nerve  do  not  act  to  advantage. 

Very  Foul  Stools. — These  are  caused  by  decomposi- 
tion of  the  albuminoid  or  proteid  principles  of  the  food 
(54). 

Profuse,  Colorless,  Watery  Stools,  with  little  fecal  mat- 
ter, are  doubtless  caused  by  an  infective  germ,  akin  to 
that  of  Asiatic  cholera.  This  condition  is  known  as 
cholera  infantum.  The  fluid  consists  largely  of  serum 
exuded  from  the  blood-vessels,  and  the  infant  is  quickly 
drained  as  if  by  a  hemorrhage.  This  is  often  preceded 
by  a  few  foul  fecal  stools. 

It  is  rare  to  see  one  of  these  types  by  itself.  With 
the  exception  of  the  last,  they  may  be  seen  in  all  combi- 
nations. 


SELECTION    OF   FOOD.  249 

Food  for  Infants  with  Normal  Stools. 

157-  It  is  always  best  to  begin  by  feeding  young  in- 
fants, every  two  hours,  two  ounces  of  a  mixture  of  nine- 
ounce  top  milk  with  eight  parts  of  diluent  to  which  has 
been  added  one-twentieth  sugar,  as  previously  described 
(I39)^  and  watch  the  effect.  If  this  is  well  borne,  as 
shown  by  normal  stools,  absence  of  colic,  and  restful 
sleep,  feed  two  and  one-half  to  three  ounces  of  a  less 
diluted  mixture,  and  follow  this  process  until  the  feeding 
mixture  is  one-fourth  nine-ounce  top  milk;  then  substi- 
tute sixteen-ounce  top  milk  (136),  and  use  one  part  with 
two  parts  of  diluent,  and  finally  equal  parts  of  this  top 
milk  and  diluent.  When  the  top  milk  is  less  than  one- 
third  of  the  mixture,  one  part  of  sugar  to  thirty  parts 
of  food  should  be  used.  By  this  method  the  infant's  di- 
gestive tract  is  gradually  accustomed  to  digest  the  curds 
of  cow's  milk;  but  not  until  a  mixture  that  is  one-third  to 
one-half  top  milk  is  used  does  the  infant  get  as  much  pro- 
tein as  a  breast-fed  baby.  This  method  of  feeling  the  way 
along  should  also  be  followed  when  the  infant  is  receiving 
part  of  its  nourishment  from  the  breast. 

The  percentages  of  fat  in  the  infant's  food  may  be  de- 
creased by  diluting  the  top  fourteen,  eighteen,  or  twenty 
ounces  from  the  bottle,  instead  of  the  top  nine  or  six- 
teen ounces. 

It  is  impossible  to  give  exact  quantities  to  be  fed  at 
different  ages.  All  that  can  be  done  is  to  start  with  a 
general  idea  of  the  quantity  required  by  the  average  in- 
fant at  various  ages.  Begin  with  a  weak  mixture  and 
work  up  as  rapidly  as  possible  to  the  point  of  toleration 


250 


INFANT   FEEDING. 


in  all  cases  (139).  The  graduate  that  may  be  used  for 
measuring  food  (Fig.  65)  shows  about  the  stomach  capac- 
ity at  different  ages,  but  it  should  be  remembered  that 
some  of  the  food  leaves  the  stomach  almost  as  soon  as 


Fig.  65.— Approximate  Stomach  Capacity  at  Different  Ages. 

swallowed,  so  the  size  of  an  infant's  stomach  is  not  neces- 
sarily an  exact  measure  of  the  quantity  of  food  it  should 
have  at  a  feeding.  Few  young  infants  will  be  satisfied 
with  a  feeding  no  larger  than  the  capacity  of  the  stomach 
as  measured  by  filling  the  stomach  of  a  cadaver  with  water. 


SELECTION    OF   FOOD. 


251 


Fig.  66. — Baby  Food 
Warmer. 


No  infant  should  be  left  on  a  mixture  containing  less  than 
one-fifth  top  milk  for  any  length  of  time  unless  absolutely 
necessary,  as  the  protein  is  too  low  in  quantity.     Here 
dextrinized   gruels  are  of   great  value   as 
diluents,  as  they  increase  the  amount  of 
protein  in  the  infant's  food,  which  is  of 
great  advantage  (128). 

158.  Before  giving  the  infant  its  bottle, 
the  food  should  be  warmed  by  placing  it 
in  warm  water.  A  very  convenient  "  Baby 
Food  Warmer"  is  shown  in  Fig. 66.  The 
heater  is  an  alcohol  stove  which  will  warm 
an  eight-ounce  feeding  in  from  three  to 
five  minutes.  It  is  small  enough  to  be 
carried  when  travelling. 

Remove  the  cotton  stopper  from  the  bottle  and  fit  on 
the  nipple.  Pure  rubber  nipples  should  be  used.  These 
will  easily  stretch  several  inches  and  resume 
their  original  shape ;  inferior  nipples  do  not 
stretch  easily.  Invert  the  bottle  and  see 
that  the  hole  in  the  nipple  is  large  enough 
to  allow  the  food  to  drop  slowly,  not  run 
in  a  stream.  Before  feeding  it  is  necessary 
to  see  that  it  is  not  too  hot.  A  practical 
method  of  testing  the  warmth  of  food  sug- 
gested by  Marianna  Wheeler  consists  in 
allowing  a  few  drops  to  fall  on  the  wrist. 
The  nipple  should  never  be  put  in  the  at- 
tendant's mouth.  The  infant  should  be  held  while  nursing 
in  as  nearly  the  natural  position  as  possible,  and  should 
not  be  allowed  over  twenty  minutes  in  which  to  take  food. 


8aw 


Fig.  67.— Nipple. 


o- 


INFANT   FEEDING. 


Regularity  in  feeding  should  be  followed,  and  the  hours 
at  which  feedings  are  to  be  given  should  be  written  down 
for  the  mother  or  nurse,  as  in  breast  feeding  (114).  Noth- 
ing but  cooled  boiled  water  should  be  offered  between 
meals.  It  is  well  to  remember  that  infants  become  thirsty. 
The  infant  should  be  weighed  each  week  and  a  record 
kept  of  its  weight  (173).  Unless  there  is  a  steady  gain  in 
weight  something  is  wrong.  If  the  infant 
shows  no  signs  of  discomfort  or  indigestion, 
use  a  stronger  food — that  is,  more  top  milk 
and  less  diluent.  If  there  is  indigestion  and 
colic,  the  food  will  have  to  be  changed  as 
described  in  another  place  (161). 

If  the  infant  is  restless  at  night  or  if  one 
feeding  is  vomited,  it  is  well  to  substitute  a 
feeding  of  the  diluent  (133),  which  will  give 
the  digestive  tract  a  rest  and  at  the  same  time 
maintain  the  infant's  strength.  This  is  espe- 
cially beneficial  in  warm  weather  when  the 
digestive  function  is  depressed.  When  an  in- 
fant vomits  rancid  curds  shortly  after  feeding, 
use  weaker  top  milk ;  that  is,  if  nine-ounce  top  milk  causes 
trouble,  try  sixteen-ounce  top  milk  or  even  plain  milk  (132). 
This  reduces  the  quantity  of  fat  that  becomes  rancid  in 
the  infant's  food.     Sugar  ma)'  also  be  reduced  a  half. 

159-  Pasteurization  of  Food. — When  good  fresh  milk 
can  be  obtained,  it  is  better  not  to  pasteurize,  as  owing  to 
the  germicidal  property  of  properly  handled  fresh  milk 
little  bacterial  change  will  have  taken  place ;  but  when  the 
milk  is  of  doubtful  quality  and  freshness,  the  infant's  food 
should  be  pasteurized  as  soon  as  made  up  (140).     If  the 


Fig.  68.-  Bottle 
Brush. 


SELECTION    OF   FOOD. 


253 


milk  reddened  test  paper  (139),  lime  water,  syrup  of  lime,  or 
bicarbonate  of  soda  (133)  should  be  added  to  the  food  after 
pasteurization,  until  the  reddened  paper  turns  blue  again. 
The  natural  enzymes  of  milk  are  destroyed  at  about 
1580  F.,  but  it  is  doubtful  if  they  have  any  practical  value 
as  digestive  aids,  as  it  takes  months  for  them  to  produce 
much  change  in  the  proteids  of  the  milk  outside  of  the 
digestive  tract  (32  B,  61). 

Care  of  Nursery  Utensils. 

160.  After  the  food  has  been  made  up  or  the  nursing 
bottles  have  been  used,  the  dipper,  measures,  bottles,  and 
anything  that  has  had  milk  in  should  be  first  rinsed  with 
cold  water,  then  washed  with  hot  water  and  soap  or  some 
of  the  washing  powders,  and  a  bottle  brush.  If  hot  water 
is  used  first,  the  milk 
"  cooks  on"  the  uten- 
sils, and  it  is  then 
difficult  thoroughly 
to  clean  them. 

Cleanliness  is  a 
very  important  part 
of  infant  feeding,  as 
dirty  utensils  may 
harbor  bacteria  (59) 
that  cause  decompo- 
sition in  the  food  and 
hence  produce  sick- 
ness in  the  infant.  After  washing  with  hot  water  the  uten- 
sils should  be  boiled  and  the  bottles  either  kept  filled  with 
water  or  inverted  in  a  clean  place  until  wanted  for  filling. 


Fig.  60.     Oil  Stove  for  Nurserv. 


254  INFANT   FEEDING. 

The  nipples  should  be  washed  out  and  kept  lying  in  a 
cup  of  water  in  which  a  pinch  of  borax  or  boric  acid  has 
been  dissolved. 

To  be  sure  of  having  a  supply  of  boiling  water,  a  gas 
stove  or  oil  stove  should  be  in  every  nursery  outfit. 

Food  for  Infants  with  Colic,  Persistent  Vomiting, 
Abnormal  Stools,  and  Evidence  of  General 
Malnutrition. 

161.  Colic  may  be  caused  by  an  excessive  quantity  of 
proteid  in  the  food  or  by  the  infant  not  being  kept  warm 
enough,  especially  the  bowels  and  extremities.  The  ex- 
cess of  proteid  in  the  food  may  be  reduced  by  increasing 
the  dilution.  Persistent  vomiting  may  be  caused  by  feed- 
ing too  great  a  quantity  at  a  time ;  from  too  much  fat  or 
cream  in  the  food,  or  by  poisonous  products  in  the  milk, 
the  result  of  bacterial  growth.  Abnormal  stools  may  con- 
tain curds  of  casein  or  fat,  fermenting  sugar,  and  mucus 
resulting  from  the  undigested  food  irritating  the  intestine. 
Digestion  is  at  a  standstill  and  the  infant  is  living  partly 
on  its  own  tissues,  hence  the  malnutrition. 

As  all  these  conditions  are  often  seen  at  the  same 
time,  it  is  not  always  practical  readily  to  discover  the 
cause  of  the  digestive  disturbance.  This  belongs  more  to 
research  work  than  to  practical  infant  feeding.  The  prob- 
lem for  the  feeder  is  to  nourish  the  infant  and  re-establish 
the  digestive  process.  Here  the  natural  order  of  develop- 
ment (156)  can  be  followed  with  advantage: 

1  st.  If  the  stools  show  signs  of  fermentation  or  putre- 
faction, clear  out  the  intestines  with  a  mild  purgative  (see 
Summer  Diarrhoea)  (17°). 


SELECTION    OF   FOOD.  255 

2d.  Supply  nourishment  that  will  be  absorbed  with  lit- 
tle digestive  effort  and  spare  the  infant's  tissues. 

3d.  When  the  stools  become  normal,  gradually  add 
food  that  will  stimulate  the  flow  of  digestive  juices  and 
develop  the  functions  of  the  stomach. 

162.  When  milk  feedings  cause  digestive  disturbance 
as  just  described,  it  is  best  to  stop  them  at  once  and  feed 
gruels,  dextrinized  gruels,  or  egg-water  (137) ;  these  will 
generally  be  retained  and  assimilated,  and  furnish  consid- 
erable nourishment.  When  the  digestive  disturbance  has 
subsided,  a  teaspoonful  of  plain  milk  may  be  added  to  a 
two-ounce  feeding  and  the  quantity  gradually  increased 
and  sugar  added  as  fast  as  the  infant's  digestion  will  per- 
mit. In  this  class  of  cases  the  addition  of  lime  water  or 
syrup  of  lime  until  the  food  is  alkaline  to  litmus  paper 
may  be  beneficial ;  one  part  of  lime  water  to  twenty  parts 
of  food  is  often  used.  It  should  be  remembered  that  the 
syrup  of  lime  is  about  thirty  times  as  strong  as  lime  water; 
hence  one  teaspoonful  of  syrup  of  lime  equals  about  four 
ounces  of  lime  water. 

163.  Occasionally  infants  will  be  met  who  cannot  di- 
gest the  casein  of  cow's  milk  without  constant  difficulty 
and  distress.  The  shifting  of  percentages  or  altering  the 
diluent  appears  to  make  little  difference  in  these  cases,  as 
the  infant  continues  to  fret  and  to  show  a  stationary  or  los- 
ing weight.  This  may  be  the  culmination  of  many  at- 
tacks of  indigestion,  or  sometimes  it  seems  to  be  sort  of 
gouty  or  lithaemic  heritage,  perhaps  coming  directly  from 
the  parents,  and  showing  itself  in  such  a  form  at  this 
early  age.  After  a  fair  and  intelligent  trial  of  ordinary 
cow's  milk  has  proved  unsuccessful,  it  is  best  to  put  the 


256  INFANT    FEEDING. 

infant  on  condensed  milk.  The  process  used  in  condens- 
ing appears  to  produce  a  change  in  the  casein  that  makes 
it  easier  of  assimilation  in  this  class  of  cases.  Fresh  con- 
densed milk  is  preferable,  but  when  this  cannot  be  ob- 
tained the  best  brands  of  sweetened  condensed  milk  may 
be  used.  Sometimes  it  is  necessary  to  use  as  little  as  one 
teaspoonful  to  four  ounces  of  plain  or  dextrinized  gruel 
(137)  at  the  start.  If  this  is  well  borne  the  quantity  of 
condensed  milk  should  be  rapidly  increased.  After  the 
dilution  has  reached  one  to  fifteen,  equal  parts  of  con- 
densed milk,  and  cream  removed  from  a  bottle  of  milk, 
and  mixed,  should  be  used  for  dilution,  which  may  be  re- 
duced gradually  to  one  to  five  or  six  parts  of  diluent  (com- 
position about  two  to  three  per  cent  fat,  one  to  one  and 
one-half  per  cent  proteid,  six  to  eight  per  cent  sugar). 

164.  When  only  small  quantities  of  food  can  be  di- 
gested, one  teaspoonful  of  beef  juice  (152)  may  be  added 
to  a  two-ounce  feeding.  This  is  slightly  nourishing  and 
acts  as  a  digestive  stimulant  (13).  Occasionally  when 
highly  diluted  milk  is  not  well  digested  a  much  smaller 
quantity  of  more  concentrated  milk  food  will  be  re- 
tained and  digested,  or  peptonized  milk  (*47)  may 
succeed. 

When  milk  of  any  kind  is  not  tolerated,  white  of  egg 
and  dextrinized  gruel  or  yolk  of  egg  with  the  same  (149) 
may  be  tried.  Occasionally  dextrinized  gruel  will  not  be 
tolerated.  Then  resort  may  be  had  to  whey,  meat  broths, 
or  white  of  egg  in  water  (148),  getting  back  to  milk  feed- 
ings as  soon  as  possible,  always  bearing  in  mind  that  the 
aim  is  to  have  the  infant  ultimately  take  between  three 
and  five  per  cent  of  fat,  one  and  two  per  cent  of  proteids 


SELECTION    OF   FOOD.  257 

(mixture  one-third  to  one-half  top  milk),  and  five  to  eight 
per  cent  of  sugar. 

Only  general  rules  can  be  given  for  feeding  these 
cases.     They  may  be  summarized  as  follows : 

1.  Maintain  nutrition  with  any  form  of  food  that  will 
be  readily  absorbed  (dextrinized  gruel,  whey,  egg  mixture). 

2.  When  the  stools  become  normal,  give  food  that  will 
gradually  re-establish  the  digestive  process  (add  small 
quantity  of  milk). 

3.  Return  to  rnilk  feeding  (139)  as  soon  as  possible. 

4.  The  fact  that  all  the  food  that  is  utilized  combines- 
with  the  oxygen  of  the  air  we  breathe  should  not  be  over- 
looked, and  hence  attention  should  be  paid  to  the  air  sup- 
ply as  well  as  to  the  food. 

It  should  be  remembered  that  fats  retard  gastric  secre- 
tion, and  that  excess  of  sugar  promotes  the  flow  of  an 
acid  gastric  juice ;  therefore  these  ingredients  should  be 
reduced  in  quantity  when,  there  is  gastric  disturbance. 
Excessive  vomiting  may  be  clue  to  mucus  in  the  stomach, 
which  may  be  removed  by  stomach  washing  (165) ;  or  to 
nephritis.  In  all  forms  of  fevers,  fats  should  be  reduced 
in  quantity,  and  easily  assimilated  carbohydrates  in  the 
form  of  dextrinized  gruels  (137)  supplied  along  with  milk, 
to  reduce  as  much  as  possible  the  excessive  destruction  of 

protein  tissues  that  takes  place  in  fevers  (13,  14,  19,  25). 
17 


CHAPTER    XXIV. 

FEEDING  BY  GAVAGE— NASAL  FEEDING-REC- 
TAL FEEDING— FEEDING  PREMATURE  IN- 
FANTS. 

165.  Cases  are  not  infrequently  met  with  in  which  an 
infant  cannot  or  will  not  take  sufficient  nourishment  by- 
swallowing.  It  will  then  be  necessary  to  feed  wholly  or 
in  part  by  the  stomach  tube.  This  proceeding  is  often 
easier  than  it  looks ;  all  that  is  needed  is  a  glass  funnel, 
to  which  is  attached  a  short  rubber  tube,  and  this  to  a  soft 
catheter,  by  a  short  piece  of  glass  tubing  placed  between 
the  rubber  tube  and  catheter,  so  that  the  flow  of  the  fluid 
can  be  seen.  The  infant  is  placed  in  a  recumbent  posi- 
tion, with  the  arms  bandaged  to  the  sides  of  the  body  or 
fastened  by  a  towel  tightly  pinned  around ;  an  assistant 
steadies  the  head,  and  the  tube  is  quickly  passed  through 
the  mouth ;  when  it  reaches  the  back  wall  of  the  pharynx 
a  little  force  is  required  to  deflect  it  downward,  when  it  is 
easily  passed  into  the  stomach.  In  cases  in  which  the  ton- 
sils are  much  swollen,  as  in  diphtheria,  the  tube  may  be 
passed  through  the  nostril,  taking  care  to  pass  the  tube 
through  the  inferior  meatus  along  the  floor  of  the  nose. 
It  is  sometimes  a  little  more  difficult  to  get  the  tube 
through  the  nose,  besides  being  apt  to  cause  more  dis- 
comfort. Fluid  will  flow  more  readily  when  the  tube  is 
full  as  it  passes  into  the  stomach.     Otherwise  the  column 


FEEDING   BY   GAVAGE. 


259 


Fig.  70. — Stomach  Tube 


of  air  in  the  tube  may  offer  some  resistance  to  the  flow  of 
the  nutrient  fluid.  This  can  be  obviated  by  filling  the 
tube  with  warm  water  or  the  fluid  food,  and  then  pinch- 
ing the  tube  just  below  the  funnel.  The  fluid  will  then  not 
run  out  of  the  tube,  which  can  be  passed  into  the  stomach ; 
when  it  is  in  place 
the  funnel  is  filled,  after 
which  the  grasp  on  the 
tube  is  relinquished,  and 
the  fluid  will  easily  flow 
into  the  stomach.  When 
the  tube  is  withdrawn, 
it  should  be  pinched 
again  to  prevent  drops 
trickling  out  and  irri- 
tating the  pharynx,  as  vomiting  may  be  caused  by 
such  irritation. 

It  is  better  to  give  nourishment  in  rather  higher 
dilution  than  has  been  usual  for  the  infant;  often 
partly  digested  food  is  required  when  gavage  is 
employed.  The  intervals  between  feeding  should 
also  be  longer  than  when  nourishment  is  given  by 
natural  means,  and  the  stomach  must  not  be  filled 
too  fast.  Where  gavage  is  continually  employed, 
the  stomach  should  be  washed  out  every  day  or  so  with 
warm  water  before  feeding,  as,  by  removing  mucus  or 
particles  of  food,  digestion  and  absorption  are  improved. 

In  stomach  washing,  pour  in  water  through  the  tube 
as  in  feeding.  Then  lower  the  funnel  so  that  the  water 
can  siphon  out  of  the  stomach. 

Premature  infants  and    atrophy  cases  at  term   may 


260  INFANT    FEEDING. 

sometimes  be  fed  to  advantage  by  gavage ;  also  harelip  or 
cleft-palate  babies,  who  swallow  with  difficulty ;  and  after 
certain  operations  upon  the  mouth.  Some  badly  nour- 
ished babies  absolutely  refuse  to  take  sufficient  nourish- 
ment, which  may  be  corrected  by  the  use  of  the  stomach 
tube.  The  author  has  seen  cases  in  which  one  or  two  full 
feedings  thus  given  was  followed  by  the  baby  voluntarily 
taking  a  proper  amount.  In  meningitis,  and  when  there 
is  complete  or  partial  unconsciousness  from  any  cause, 
gavage  may  be  employed  with  good  results.  The  same 
may  be  said  of  diphtheria  accompanied  by  much  swelling 
of  the  throat,  and  particularly  after  intubation.  In  the 
latter  case,  feeding  by  gavage  should  always  be  employed, 
at  least  for  the  first  day  or  so.  Later  on  the  child  may 
be  cautiously  spoon-fed  with  the  head  in  a  low  position, 
and  viscid  substances,  like  condensed  milk,  are  less  apt 
to  penetrate  the  tube.  Finally,  persistent  vomiting  is 
sometimes  relieved  by  one  or  two  feedings  by  gavage. 
When  the  stomach  tube  has  been  used  for  any  cause,  the 
child  should  be  kept  very  quiet  in  a  horizontal  position  for 
some  time  afterward ;  the  chance  of  vomiting  will  thus  be 

much  lessened. 

Rectal  Feeding. 

166.  There  is  a  great  difference  in  the  tolerance  of  the 
rectum  to  attempted  feeding  in  the  infant  as  in  the  adult. 
At  times,  such  as  in  extreme  gastric  irritability  or 
when  there  is  local  obstruction,  as  in  diphtheria  or  retro- 
pharyngeal abscess,  it  is  often  desirable  to  stop  for  a  time 
all  nourishment  by  the  mouth.  In  such  cases  we  must 
bear  in  mind  the  fact  that  the  rectum  can  absorb  but  not 
digest  food,  and  that  small  amounts  will  often  be  retained 


FEEDING   BY   GAVAGE.  261 

when  larger  amounts  are  rejected.  The  lower  bowel 
must  first  be  cleaned  by  a  moderate  injection  of  warm 
salt  solution  or  soap  suds  and  water.  From  one  to  two 
ounces  of  the  nutrient  solution  may  then  be  very  slowly 
injected,  with  the  buttocks  slightly  raised  and  tightly  held 
on  either  side  of  the  nozzle  of  the  syringe.  When,  the 
nozzle  is  withdrawn  the  buttocks  had  better  be  held  in 
close  apposition  for  a  few  moments,  to  prevent  a  leaking 
out  of  part  of  the  enema.  In  cases  in  which 
the  rectum  is  intolerant,  a  very  small  amount, 
such  as  two  or  three  drachms,  will  some- 
times be  retained.  The  occasional  addition 
of  a  fraction  of  a  drop  of  deodorized  tinct- 
ure of  opium  to  the  nutrient  enema  will 
help  to  quiet  an  over-irritated  rectum,  but 
the  susceptibility  of  very  young  infants  to 
the  constitutional  effects  of  opium  must 
always  be  borne  in  mind.  When  the  enem- 
ata  are  given  at  regular  intervals,  the  prelim- 
inary  washing  need  not  be  employed  after  FlG.  7I._Rectai 
the  first  time,  as  this  increases  the  irritability  syrmge. 

of  the  bowel.  Easily  absorbable  nutriment  must  always 
be  employed,  such  as  dextrinized  gruel,  dextrinized  gruel 
with  white  of  egg  (*49),  completely  peptonized  milk,  or 
expressed  beef  juice  and  water.  In  cholera  infantum, 
where  the  quick  loss  of  fluid  from  the  blood-vessels  threat- 
ens life,  the  injection  of  a  hot  saline  solution  into  the 
bowel  sometimes  affords  relief.  Here  again  a  small 
amount  is  often  preferable,  as  two  or  three  ounces,  or 
even  half  an  ounce,  may  be  retained  and  absorbed,  when 
a  pint  may  be  quickly  rejected. 


262  INFANT   FEEDING. 

Feeding  of  Premature  Infants. 

167.  The  difficulty  of  nourishing  premature  babies 
consists  in  the  incomplete  development  of  their  digestive 
tract,  and  the  difficulty  of  keeping  them  warm  while  at 
the  same  time  supplying  sufficient  fresh  air.  They  are 
exceedingly  dependent  upon  pure  air,  and  here  it  is  that 
most  incubators  fail.  The  author  has  treated  over  fifty 
premature  infants  in  incubators  at  the  Babies'  Wards  of 
the  New  York  Post-Graduate  Hospital,  but  with  poor  re- 
sults. This  is  attributed  to  two  factors — the  absence  of 
the  breast,  calling  for  exclusive  artificial  feeding ;  and  the 
delay  in  getting  them,  many  of  the  babies  being  blue  and 
cold  from  exposure  in  transporting  them  to  the  hospital 
when  received.  The  author  has  tried  all  kinds  of  incuba- 
tors, and  believes  that  only  those  having  a  fresh-air  inlet 
connected  with  the  outer  air  are  safe  to  use.  The  Lyon 
incubator  is  a  good  example  of  this  type.  If  such  an  in- 
cubator is  not  obtainable,  an  ordinary  soap  box  may  be 
improvised,  in  which  the  baby  is  placed,  done  up  in  cot- 
ton and  surrounded  by  hot-water  bottles.  The  top  of  the 
box  may  be  partially  covered  with  a  sheet  or  towel,  so  ar- 
ranged as  to  allow  free  access  of  fresh  air.  The  babies  at 
first  seem  to  do  best  at  an  average  temperature  varying 
from  85 °  to  900  F.  The  less  the  infant  is  disturbed  the 
better ;  at  the  same  time  proper  cleanliness  of  the  baby 
and  incubator  must  be  insisted  on,  as  these  infants  are 
very  vulnerable  to  infection  of  all  kinds.  The  most  im- 
portant factor  in  raising  them  is  to  secure  breast  milk. 
The  milk  must  be  drawn  from  the  breast  after  the  colos- 
trum period,  the  preferable  time  being  from  about  eight 


FEEDING   BY   GAVAGE.  263 

days  to  a  month  or  so  post  partum.  This  milk  must 
usually  be  diluted  one-half  with  boiled  water  or  sugar- 
water  solution.  The  best  way,  in  the  author's  experience, 
to  administer  fluid  to  these  babies  is  by  means  of  a  medi- 
cine dropper.  This  must  be  done  very  slowly,  drop  by 
drop,  taking  care  to  see  that  the  motion  of  swallowing  is 
accomplished  after  each  drop  before  giving  another.  This 
extra  care  is  required  from  the  tendency  of  the  fluid  to 
get  into  the  windpipe.  The  author  has  seen  a  number  of 
deaths  from  this  cause,  as  shown  by  autopsy. 

When  the  infant  is  too  feeble  to  swallow,  a  small 
catheter  used  as  a  stomach  tube  must  be  employed.  It 
can  be  passed  without  removing  the  baby  from  the  incu- 
bator, and  does  not  seem  to  cause  it  much  disturbance. 
As  soon  as  the  baby  grows  older  and  is  strong  enough, 
a  small  nipple  may  be  substituted.  The  exact  amount 
to  be  given  a  premature  baby  must  depend  upon  the  pe- 
riod of  utero-gestation  and  its  apparent  development.  In 
one  case,  weighing  only  two  and  a  half  pounds,  a  drachm 
every  hour  was  given  by  the  author,  with  good  results. 
In  better-favored  cases,  from  four  to  eight  drachms  can 
be  given  every  hour  or  two.  If  the  infant  thrives,  in  two 
or  three  weeks  it  can  be  given  pure  breast  milk  at  two- 
hour  intervals.  Where  it  is  impossible  to  get  breast  milk 
the  chances  of  the  premature  baby  will  be  very  poor,  but 
efforts  must  be  made  in  the  line  of  artificial  feeding. 
Both  the  fat  and  proteids  of  cow's  milk  are  digested  with 
difficulty  in  these  cases,  so  they  must  be  given  in  very 
small  amounts.  The  milk  must  be  diluted  to  represent 
fat  1  per  cent,  sugar  3  per  cent,  proteids  0.33  per  cent 
(one-tenth  nine-ounce  top  milk  plus  one-thirtieth  sugar), 


264  INFANT   FEEDING. 

of  which  a  drachm  maybe  tentatively  given  every  hour; 
if  tolerated,  gradually  increase  the  amount.  If  the  baby 
is  at  the  eighth  month,  a  little  stronger  mixture  may  be 
borne,  such  as  fat  1.5  per  cent,  sugar  5  per  cent,  proteids 
0.50  to  0.75  per  cent  (one-eighth  to  one-fifth  nine-ounce 
top  milk  plus  one-twenty-fifth  sugar).  Such  a  case  may 
take  from  four  to  six  drachms  every  hour  and  a  half. 
The  exact  amount  must  depend  upon  the  general  devel- 
opment of  the  baby,  bearing  in  mind  that  the  stomach  of 
the  baby  at  term  has  a  capacity  of  about  an  ounce.  Some 
cases  cannot  digest  ordinary  cow's  milk,  and  then  a  trial 
may  be  made  of  whey,  expressed  beef  juice,  egg  water,  or 
highly  diluted  condensed  milk.  In  a  case  recently  seen 
with  Drs.  Hurlburt  and  Sherill,  of  Stamford,  Conn.,  a 
feeble  incubator  baby  was  successfully  fed  with  undiluted 
ass'  milk  for  about  a  month,  gaining  in  weight  and 
strength.  This  milk  then  giving  out,'  the  baby  was  put 
on  a  wet-nurse  and  continued  to  thrive. 


CHAPTER    XXV. 

CONSTIPATION. 

168.  Constipation  as  well  as  diarrhoea  are  relative 
terms,  and  refer  more  to  the  character  than  the  frequency 
of  stools.  A  constipated  stool  in  an  infant  is  usually  dry 
and  hard  and  voided  with  some  difficulty.  One  or  two 
such  stools  may  be  passed  daily  with  evidence  of  intesti- 
nal discomfort,  and  call  for  dietetic  treatment.  In  the 
nursing  infant  the  mother  is  herself  frequently  consti- 
pated, and  treatment  must  first  be  directed  to  her,  as 
when  she  is  properly  regulated  the  infant  may  need  no 
further  attention.  Stewed  fruit,  figs,  prunes,  oatmeal  and 
cream,  unbolted  bread,  and  similar  articles  of  diet  may  be 
tried  with  the  mother,  with  plenty  of  outdoor  exercise. 
It  may  be  necessary  to  cut  off  milk  in  part,  or  to  give  it 
diluted  with  oatmeal  gruel  to  which  cream  is  added.  A 
glass  of  cold  water  or  Vichy  immediately  upon  rising  has 
a  favorable  effect  in  opening  the  bowel.  Tea  should  be 
avoided.  If  these  measures  do  not  suffice,  some  of  the 
tonic  laxatives,  such  as  cascara,  aloin,  nux  vomica,  and 
hyoscyamus  may  be  tried.  The  commercial  mixtures  of 
malt  extract  and  cascara  are  usually  efficient  and  agree- 
able. 

When  the  mother  has  been  regulated  and  the  infant 
remains  constipated,  there  is  usually  a  deficiency  of  fat  in 
her  milk,  often  accompanied  by  a  high  percentage  of  pro- 
teids.     If  this  cannot  be  corrected  by  a  meat  diet  and 


266  INFANT   FEEDING. 

plenty  of  exercise  (20),  a  little  fat  maybe  administered 
to  the  baby  just  after  nursing.  A  small  teaspoonful  of 
cream  two  or  three  times  daily  given  in  this  way  may 
correct  the  infant's  constipation;  a  half-teaspoonful  of 
sweet  oil  will  also  serve  the  same  purpose.  The  efficacy 
of  the  oil  is  sometimes  increased  by  combining  with  it  a 
little  sugar  and  water,  a  small  lump  of  loaf  sugar  being 
dissolved  in  a  teaspoonful  of  water  and  given  with  the  oil. 
A  half  teaspoonful  of  cod-liver  oil  may  also  be  employed 
in  the  same  way. 

The  nursing  baby  may  be  constipated  from  the  moth- 
er's milk  being  deficient  in  both  fats  and  proteids,  or 
from  an  insufficient  quantity  of  it.  If  efforts  to  correct 
this  condition  fail,  it  may  be  necessary  to  supplement  the 
breast  by  the  bottle  in  order  to  increase  the  volume  of  the 
stool  (27)  and  thus  relieve  the  constipation.  As  a  rule, 
bottle-fed  babies  are  more  apt  to  suffer  from  constipation 
than  those  on  the  breast.  In  the  former  cases  the  condi- 
tion may  be  corrected  by  increasing  the  fat  in  the  feeding 
mixture.  According  to  the  dilution  often  recommended 
for  young  babies,  the  fat  barely  reaches  two  per  cent  when 
poor  milk  is  used  in  making  the  mixture.  By  using  less 
diluent  or  a  richer  top  milk  (132),  we  may  run  the  fat  up 
to  three  per  cent  and  thereby  improve  nutrition  as  well  as 
relieve  constipation.  During  the  first  six  months  or  so  of 
the  first  year  the  baby  usually  thrives  best  on  a  mixture 
containing  three  per  cent  fat  and  one  per  cent  milk 
proteids,  while  later  in  the  year  four  per  cent  fat  and  one 
and  one-half  to  two  per  cent  milk  proteids  are  indicated 
(143).  The  neglect  to  administer  percentages  suitable  to 
the  age  and  condition  of  the  infant  is  responsible  for  a 


CONSTIPATION.  267 

good  deal  of  constipation,  a  habit  it  is  sometimes  difficult 
to  correct  even  when  the  cause  is  removed.  A  change  in 
the  diluent  employed  will  sometimes  be  necessary;  if  gru- 
els are  used,  oatmeal  is  more  laxative  than  barley  or 
wheat  flour.  Infants  of  a  year  old  may  be  given  chicken 
tea,  which  is  somewhat  laxative,  and  beef  tea  may  have 
the  same  effect ;  expressed  beef  juice  sometimes  favors 
an  action  of  the  bowels.  A  teaspoonful  to  a  tablespoon- 
ful  of  orange  juice  given  in  the  morning  often  has  a  laxa- 
tive action  upon  the  infant.  The  free  use  of  water,  be- 
tween nursings  or  feedings,  tends  to  prevent  too  great 
consistency  of  the  stools,  one  of  the  common  accompani- 
ments of  constipation. 

For  children  of  two  or  three  years,  fresh  fruit,  such  as 
apples,  peaches,  and  oranges,  may  be  given  in  the  morn- 
ing; stewed  fruits  of  all  kinds  are  allowable,  and  dried 
fruits,  such  as  prunes,  figs,  and  dates,  often  do  good  ser- 
vice. The  following  method  of  treating  prunes,  given  the 
author  by  Dr.  Cauldwell,  has  often  produced  favorable 
results:  Fill  a  preserve  jar  one-half  or  three-quarters  full 
of  fresh  California  prunes,  and  pour  in  boiling  hot  water 
to  fill  the  jar;  next  close  the  jar  and  stand  in  a  warm 
place  for  six  or  eight  hours.  During  this  time  the 
prunes  become  full  and  swollen  and  the  pulp  is  very  soft. 
The  water  is  then  drained  off  and  the  prunes  are  spread  on 
a  plate  so  that  the  skins  may  dry  quickly.  They  are  now 
ready  to  eat ;  split  open  and  use  the  pulp  only.  Give  the 
pulp  of  three  to  six  prunes  before  breakfast  each  morning 
with  a  glass  of  cold  water.  The  laxative  effect  of  the 
prunes  is  thus  much  enchanced,  and  they  are  usually 
readily  taken  in  this  form  by  children. 


268  INFANT   FEEDING. 

Crandall  has  stated  that  for  constipated  babies  it  is  a 
good  plan  to  give  prunes  that  have  been  boiled  with  a 
few  senna  leaves. 

The  following  "  Fruit  Tablets  "  are  agreeable  and  effi- 
cacious: Take  four  ounces  each  of  raisins,  figs,  and  dates, 
and  two  ounces  of  ground  senna  leaves;  remove  the 
seeds  from  the  raisins  and  dates,  and  finely  chop  the  fruit; 
then  mix  on  a  table,  adding  the  senna  to  the  chopped 
fruit  little  by  little,  putting  in  sherry  enough  to  make  a 
paste ;  roll  into  a  mass  half  an  inch  thick,  and  cut  into 
half  inch  squares;  place  the  tablets  between  sheets  of 
paraffin  paper  in  a  box.  One  or  two  of  these  tablets  may 
be  given  at  night  and  repeated  in  the  morning  if  neces- 
sary to  get  the  result. 

It  may  be  desirable  to  curtail  the  milk  in  cases  of  ob- 
stinate constipation  or  to  add  cream  to  what  is  taken. 
The  coarse  cereals,  such  as  oatmeal,  unbolted  bread,  and 
all  the  green  vegetables,  may  be  given  at  two  years. 
These  foods,  by  their  saline  and  fibrous  contents,  have  a 
stimulating  effect  upon  the  mucous  and  muscular  coat- 
ings of  the  intestine,  and  increase  the  quantity  of  fecal 
matter  (27). 

Very  often  the  trouble  consists  in  a  sluggish  action  of 
the  unstriped  muscular  fibres  of  the  bowel,  which  suit- 
able diet  is  not  sufficient  to  correct.  Deep  massage  of  the 
bowel,  beginning  at  the  right  iliac  fossa  and  extending 
around  the  course  of  the  large  intestine,  may  aid  muscu- 
lar action  if  thoroughly  performed  twice  daily.  The  use 
of  suppositories  and  injections  also  stimulates  the  muscles 
to  more  vigorous  action.  For  occasional  use,  glycerin 
suppositories  are  very  efficient,  but  if  employed  too  fre- 


CONSTIPATION.  269 

quently  are  apt  to  irritate  the  rectum.  For  continued 
use,  gluten  or  soap  suppositories  serve  best.  The  fault  in 
constipation  of  young  infants  is  often  at  the  lower  end  of 
the  large  intestine.  Owing  to  the  length  of  the  sigmoid 
flexure  during  infancy,  this  part  of  the  bowel  is  sharply 
curved,  with  a  resulting  tendency  to  retard  the  descent 
of  fecal  matter  just  above  the  outlet  of  the  bowel.  A 
bland  suppository,  or  even  passing  the  end  of  a  finger 
through  the  anal  ring,  will  often  cause  the  bowel  to  empty 
itself.  The  passage  of  a  healthy  digested  stool  after  such 
a  manipulation  will  prove  that  there  is  no  essential  fault 
in  diet  or  digestion,  but  simply  a  sluggishness  at  the  end 
of  the  bowel.  If  fecal  matter  is  higher  up,  an  injection 
of  two  or  three  ounces  of  soap  suds  and  water,  salt  and 
water,  or  sweet  oil  and  water  will  be  required  for  relief. 
In  obstinate  cases  a  teaspoonful  of  glycerin  in  an  ounce 
of  water  will  usually  have  a  quick  effect. 

A  constipated  infant  should  be  constantly  observed 
and  treated  until  the  condition  is  relieved,  as  most  of  the 
chronic  cases  in  later  life  have  their  beginnings  in  early 
life.  No  structure  of  the  body  is  more  amenable  to  habit 
than  the  bowel ;  hence  the  importance  of  starting  right. 
As  soon  as  the  baby  can  stand,  it  should  be  placed  upon 
the  chair  or  chamber  at  regular  intervals.  Yale  has 
called  attention  to  the  importance  of  placing  the  child 
upon  a  low  seat  with  the  feet  upon  the  floor,  as  it  can 
then  strain  to  better  advantage. 


CHAPTER    XXVI. 

SUMMER    DIARRHOEA. 

169.  The  cause  of  the  diarrhceal  diseases  of  infancy 
so  common  during  the  summer  months  is  not  positively 
known,  though  there  can  be  little  doubt  that  they  are  of 
bacterial  origin.  Just  where  the  bacterial  infection  origi- 
nally takes  place  is  hard  to  tell,  although  in  many  cases  it 
is  undoubtedly  local.  It  has  been  generally  believed  in 
the  past  that  the  high  temperature  of  the  summer  months 
was  the  cause  of  the  diarrhceal  epidemics.  Heat  does 
play  an  important  part,  especially  in  depressing  the  diges- 
tive function,  but  in  the  summer  of  1901,  which  was  an 
exceptionally  hot  one,  the  number  of  deaths  from  diar- 
rhceal diseases  of  infants  throughout  New  York  State, 
outside  of  the  district  including  Greater  New  York  and 
its  suburbs,  was  only  a  little  over  half  of  that  of  the  pre- 
vious summer,  which  was  not  so  hot.  The  amount  of 
rainfall  also  seems  to  have  little  or  no  effect  on  the  num- 
ber of  deaths  from  diarrhceal  diseases  of  infancy. 

The  milk  supply  has  come  in  for  its  share  of  condem- 
nation as  the  principal  cause  of  diarrhceal  diseases;  un- 
doubtedly the  milk  supply  is  a  prominent  factor,  but 
there  must  be  still  other  sources  of  infection,  as  breast-fed 
infants  are  sometimes  attacked. 

If  the    milk  supply  was  the  exclusive  cause  of  the  dis- 
ease, there  should  be  a  larger  proportionate  number  of 


SUMMER   DIARRHCEA. 


271 


deaths  in  cities  like  New  York,  whose  milk  is  twenty- 
four  to  forty-eight  hours  old  when  received,  than  in  the 
country  where  the  milk  is  produced.  New  York's  milk 
supply  is  drawn  from  a  wide  range  of  country,  but  it  is 
found  on  examining  the  death  statistics  that  in  some  years 
there  is  a  great  increase  in  the  number  of  deaths  in  the 
country  districts  where  the  milk  is  produced,  and  only  a 
slight  increase  in  Greater  New  York;  in  other  years  an 
increase  in  the  country  and  a  falling  off  in  the  city  is 
found,  as  will  be  seen  by  the  following  figures  obtained 
from  the  New  York  State  Board  of  Health : 

Deaths  from  Acute  Diarrhceal   Diseases,   May  ist  to  November  ist, 

Inclusive. 


Country  districts.  . 

Greater   New  York 

and  suburbs  .... 


2,550 
5,943 


2,721  3,046 
5,477  5,244 


2,727 
5,559 


1896. 


3,039 
4,908 


1897. 


2,086 
4,340 


2,833 
4,868 


1899.  I  1900. 

1 

2,187  3,202 


3,557 


3,867 


1,89s 
6,115 


It  is  improbable  that  there  is  enough  variation  in  the 
methods  of  handling  milk  from  year  to  year  to  account 
for  this  fluctuation  in  the  number  of  deaths.  There 
must  be  some  local  infection.  In  1901  the  Borough  of 
Manhattan  of  the  city  of  New  York  was  torn  up  from  one 
end  to  the  other  for  the  purpose  of  building  a  subway. 
Sewers  were  opened  and  changed,  and  dust  was  every- 
where. In  the  country  districts,  where  the  milk  was  pro- 
duced, there  was  a  large  falling  off"  in  the  number  of 
deaths  from  diarrhceal  diseases,  as  previously  mentioned, 
while  in  the  district  which  included  Manhattan  the  num- 
ber of  deaths  was  almost  double  that  of  the  previous 
year.  It  is  evident  that  there  must  have  been  a  local  in- 
fection that  caused  this  (62). 


272  INFANT   FEEDING. 

At  the  Wisconsin  Experiment  Station  there  has  been 
worked  out  what  is  known  as  a  curd  test,  by  which  the 


Z*^\ 

-  ■■  . 

K  i 

'r-.m: 

>  .9 

;  i 

■_  -  ■ 

-'    -iL^^Bl 

Fig.  72. — Rennet  Curd  of  Milk  when  Lactic  Bacteria  Predominate.     (Russell.) 

character  of  the  bacterial  changes  in  the  milk  may  be  de- 
termined and  the  source  of  the  infection  located. 

A  sample  of  milk  is  curded  by  rennet,  and  the  whey 
which  contains  most  of  the  sugar  of  the  milk  drained  off ; 
the  curd  is  then  kept  at  a  temperature  of  about  ioo:  F. 
for  several  hours. 


Fig.  73. — Rennet  Curd  of  Milk  when  Gas-Producing  Bacteria  Predominate.     (Russell.) 

The  normal  fermentation  of  milk  is  souring,  in  which 
the  sugar  is  changed  into  lactic  acid  by  lactic  bacteria; 


SUMMER   DIARRHCEA.  273 

when  this  change  takes  place  the  curd  becomes  firm  and 
uniform  in  texture.  However,  if  decomposition  or  other 
kinds  of  bacteria  that  attack  proteids  (54)  are  present, 
they  find  favorable  conditions  for  growth  in  the  curd 
which  contains  little  sugar,  and  soon  outstrip  the  lactic 
bacteria  in  growth  (52) .  Their  presence  is  shown  by  the 
production  of  gas,  which  causes  the  curds  to  rise  like 
bread  dough,  or  in  foul  offensive  odors  resulting  from  the 
decomposition  of  the  proteid  of  the  curd. 

Both  of  these  abnormal  fermentations  are  very  com- 
mon in  milk  during  July  and  August,  the  months  in 
which  there  is  generally  the  greatest  number  of  deaths 
from  diarrhceal  diseases. 

At  cheese  factories  these  bacterial  changes  are  partic- 
ularly troublesome,  and  a  great  deal  of  time  and  study 
has  been  devoted  to  locating  the  source  of  the  infection. 
The  curd  test  has  proved  to  be  valuable  for  this  purpose. 
By  making  a  curd  from  the  milk  of  each  farmer  and  re- 
jecting the  milk  that  produces  gassy  or  foul  curds,  it  has 
been  possible  to  overcome  the  trouble.  By  following  this 
same  method  with  the  milk  of  each  cow,  it  has  been  pos- 
sible to  discover  the  infectious  material,  which  is  almost 
invariably  dust  or  filth.  It  has  been  found  that  no  mat- 
ter how  much  care  has  been  devoted  to  producing  the 
milk,  if  it  becomes  slightly  infected  with  dust  or  filthy 
water  that  contains  these  bacteria,  they  will  rapidly  grow 
and  elaborate  their  characteristic  products. 

In  cases  of  summer  diarrhoea  there  is  generally  a  great 
deal  of  gas  formed  in  the  intestine,  and  many  thin,  sour 
stools  containing  undigested  curds  of  milk  are  passed. 
In  some  instances  the  stools  which  contain  undigested 


274  INFANT   FEEDING. 

curds  are  few  but  very  foul  and  offensive,  indicating  a 
decomposition  of  proteids.  Here  are  seen  all  the 
changes  that  result  from  dust  and  filth  infecting  milk. 

For  this  reason  not  only  must  care  be  exercised  in  the 
production  of  milk  at  the  farm,  but  it  should  not  be 
opened  until  delivered  to  the  family ;  and  in  the  family 
care  should  be  used  to  keep  all  utensils  absolutely  clean. 
Pasteurizing  the  food  is  one  step  toward  preventing  the 
growth  of  these  bacteria ;  but,  if  they  gain  access  to  pas- 
teurized food  or  milk,  they  grow  even  better  than  in  fresh 
milk.  Koplik  has  called  attention  to  this  question  and 
to  the  necessity  of  the  mother  or  nurse  carefully  washing 
her  hands  after  changing  an  infant's  diapers,  as  she  may 
easily  infect  the  nipple  or  the  food  in  this  manner.  The 
soiled  napkins  should  be  immediately  placed  in  a  satu- 
rated solution  of  chloride  of  lime  and  allowed  to  soak  be- 
fore being  washed. 

There  can  be  little  error  in  concluding  that  contami- 
nation at  the  farm  is  an  important  factor  in  infecting  the 
milk;  also  that  dust,  contaminated  water,  soiled  hands, 
and  possibly  flies  at  the  home  are  also  dangerous.  The 
greater  or  less  infection  of  the  milk  from  these  sources 
after  leaving  the  farm  is  the  probable  cause  of  the  varia- 
tion in  deaths  from  diarrhceal  diseases  from  year  to  year 
in  city  and  country. 

Nature  of  Summer  Diarrhcea. 

170.  There  seem  to  be  bacteria  present  in  the  diges- 
tive tract  at  all  times,  but  their  growth  is  retarded  or 
at  least  not  harmful  when  digestion  proceeds  normally. 
During  the  heated  term  all  the  vital  functions  are  de- 


SUMMER   DIARRHCEA.  275 

pressed  and  digestion  proceeds  slowly.  The  milk  curds 
in  the  stomach  normally,  and  the  whey  containing  the 
sugar  is  expressed  (37)-  If  fermentation  instead  of  di- 
gestion takes  place,  the  lactic  bacteria  have  a  free  field  in 
the  whey,  and  the  putrefactive  or  gas-producing  bacteria 
in  the  curds,  where  they  are  protected  from  the  action  of 
what  little  digestive  juice  is  secreted.  Products  of  pro- 
teid  decomposition  resulting  from  such  conditions  are 
apt  to  be  poisonous  (54),  and  it  is  not  at  all  uncommon 
to  see  all  the  symptoms  of  toxaemia  in  infants  and  chil- 
dren with  diarrhceal  diseases,  especially  when  the  stools 
are  offensive.  Therefore  these  diarrhoeas  should  be 
looked  upon  as  cases  of  indigestion  with  a  digestive  tract 
filled  with  fermenting  and  putrefying  food. 

As  previously  stated  (169),  the  cleanest  milk  or  pas- 
teurized milk  is  quickly  rendered  harmful  by  only  a  slight 
contamination  with  this  putrefying  material ;  it  is  there- 
fore worse  than  useless  to  put  any  more  milk  or  other 
food  that  will  putrefy  into  such  a  digestive  tract  as  long 
as  this  putrefying  material  remains.  It  would  only  aggra- 
vate the  trouble.  The  diarrhoea  is  an  attempt  of  nature 
to  get  rid  of  the  offending  matter. 

The  treatment  of  this  disease  consists  of  giving  a  mild 
purgative  thoroughly  to  remove  the  putrefying  intestinal 
contents,  and  then  re-establishing  the  digestive  process. 
To.  many  mothers  the  giving  of  a  purgative  to  an  infant 
with  diarrhoea  seems  folly,  but  it  is  absolutely  essential  to 
successful  treatment,  and  if  the  mother  cannot  be  trusted 
to  give  it,  the  doctor  should  do  so  himself. 

During  an  attack  of  summer  diarrhoea  the  infant's 
food  should  be  carefully  looked  after.     The  promptness 


276  INFANT   FEEDING. 

of  recovery  will  depend  largely  on  this,  for  as  soon  as  the 
digestive  process  ceases,  owing  to  the  infection,  the  infant 
begins  to  live  on  its  own  tissues  and  there  is  a  great  and 
sudden  increase  of  protein  metabolism,  as  the  protein  is 
used  as  a  fuel.  In  infants  that  have  been  on  a  diet  poor 
in  protein  this  is  particularly  disastrous,  as  they  have  little 
reserve  protein  to  draw  on.  Such  infants  quickly  succumb. 
The  aim  in  feeding  should  be  to  sustain  the  infant  by 
the  use  of  food  (i)  that  will  not  form  a  culture  medium 
for  putrefactive  bacteria,  and  (2)  that  will  prevent  the 
abnormal  destruction  of  protein  tissue,  which  is  especially 
large  where  there  is  fever.  For  this  purpose  carbohy- 
drates stand  pre-eminent,  and  in  the  author's  experience 
gruels,  especially  when  dextrinized  (137),  are  the  best 
forms  in  which  to  give  them.  These  contain  a  small 
quantity  of  protein  in  a  form  that  will  not  easily  undergo 
putrefaction,  and  enough  carbohydrates  in  a  form  suitable 
for  prompt  absorption  to  sustain  the  infant  and  prevent 
its  own  tissues  being  destroyed  to  any  extent.  Much 
more  nourishment  can  be  given  in  the  form  of  dextrinized 
gruels  than  in  plain  cereal  waters.  If  any  fermentation 
takes  place  in  this  food,  poisonous  products  are  not 
formed,  as  carbohydrates  predominate,  which  bacteria 
change  into  lactic  acid,  that  is  not  harmful.  When 
dextrinized  gruels  cannot  be  had,  egg  water  (148)  may  be 
used,  but  this  supplies  only  about  one-fourth  as  much 
nourishment  as  the  dextrinized  gruel.  The  products  of 
egg  metabolism,  principally  urea,  must  be  excreted  by  the 
kidneys,  which  are  often  congested  and  irritated  by  the 
toxins  absorbed  from  the  intestinal  tract ;  and,  in  addi- 
tion, by  the  urine,  which    is  concentrated    and   scanty, 


SUMMER   DIARRHOEA.  277 

owing  to  the  large  loss  of  fluid  from  the  bowels.  The 
products  of  carbohydrate  metabolism  pass  off  through 
the  lungs. 

White  of  egg  is  a  pure  protein  substance  and  should 
be  used  cautiously  when  the  stools  are  foul,  but  may  be 
used  freely  when  they  are  very  sour  (52). 

Kerley,  after  studying  several  hundred  cases  of  sum- 
mer diarrhoea,  came  to  the  conclusion  that  on  a  carbohy- 
drate diet  there  was  less  systemic  poisoning,  recovery  was 
more  prompt,  and  temperature  lower  than  on  a  protein  diet. 

,    Treatment  and  Diet  in  Summer  Diarrhoea. 

171.  First:  Clean  out  the  digestive  tract  by  doses  of 
castor  oil  (one  teaspoonful)  or  divided  doses  of  calomel 
(one-tenth  grain  every  hour  until  one  grain  has  been 
taken).  If  the  stools  are  few  and  foul,  the  bowel  should 
be  irrigated  with  a  quart  of  tepid  salt  solution  (one  tea- 
spoonful  to  a  quart),  to  hasten  the  removal  of  the  putrid 
matter.  A  fountain  syringe  with  hard-rubber  tube 
should  be  used,  and  the  water  allowed  to  flow  in  gently 
until  it  runs  out  clear. 

Second :  Stop  all  milk  food  of  any  kind,  and  offer 
boiled  water;  if  this  is  retained,  feed  the  same  quantity  of 
dextrinized  gruel  or  egg  water  (137)  as  the  usual  milk 
feeding,  at  two-hour  intervals.  Rice  is  one  of  the  best 
cereals  for  this  purpose,  as  it  is  absorbed  almost  com- 
pletely. Rice  flour  or  one  of  the  flaked-rice  preparations 
(102)  may  be  used  in  preparing  the  gruel,  as  these  can  be 
cooked  in  a  few  minutes.  Barley  and  wheat  flour  come 
next  in  order.  If  the  gruel  produces  sour  acid  stools,  try 
egg  water  (148)  or  mutton  broth  (154).      When  the  stools 


278  INFANT   FEEDING. 

become  normal,  a  teaspoon/til  of  milk  should  be  added  to 
a  feeding  of  the  gruel,  and  the  quantity  cautiously  in- 
creased until  the  usual  mixture  is  taken.  Often  not  a 
drop  of  milk  will  be  tolerated  for  a  long  time.  In  these 
cases  a  strong  dextrinized  gruel  may  be  used  for  nourish- 
ment, and  to  prevent  the  infant  tiring  of  it,  barley,  rice, 
or  wheat  may  be  used  alternately.  Mutton  broth  (154) 
or  beef  juice  (152)  may  be  added  in  small  quantities  to 
act  as  flavoring  agents  and  promoters  of  digestive  secre- 
tion. Care  must  be  exercised  in  giving  meat  broth  or 
juice  in  these  cases.  Doming  has  called  attention  to 
severe  ptomain  poisoning  from  the  use  of  beef  juice  made 
from  tainted  meat ;  and  in  too  large  quantities  the  meat 
extractives  (13)  have  a  decidedly  laxative  effect. 

Drugs  to  be  Used. — Subnitrate  of  bismuth  is  the  prin- 
cipal one  used,  aside  from  castor  oil  and  calomel.  It 
should  be  given  until  the  stools  become  black.  Opium 
has  its  place,  but  should  not  be  used  before  the  intestine 
has  been  thoroughly  cleared.  Alcohol  may  be  used  up 
to  the  point  where  it  can  be  detected  in  the  breath  in 
cases  of  great  prostration,  but  many  mothers  are  apt  to 
give  too  much,  which  interferes  with  digestion  and  also 
throws  additional  strain  on  the  kidneys  in  excreting  it. 

Preventive  Measures.— -Fresh  air,  cool  sponge  baths, 
and  light  diet  are  good  preventive  measures.  The  author 
often  advises  allowing  the  smaller  children  to  play  in  a 
bathtub  containing  tepid  water  daily  in  hot  weather. 
Care  should  be  exercised  in  having  the  abdomen  kept 
warm  at  night  with  a  light  flannel  band  when  there  are  apt 
to  be  sudden  changes  of  temperature,  as  cold  may  be  the 
starting-point  of  summer  diarrhoea. 


CHAPTER    XXVII. 
DIET   DURING   SECOND   YEAR. 

172.  The  diet  during  the  second  year  requires  careful 
consideration,  as  this  is  a  period  of  transition  between  the 
breast  or  bottle  and  the  ordinary  mixed  diet  of  later  child- 
hood. It  is  a  time  of  rapid  growth,  with  cutting  of  teeth, 
when  new  functions  are  inaugurated,  all  of  which  require 
watching.  The  common  mistake  in  feeding  is  to  allow 
too  great  a  variety,  thus  taxing  the  digestive  powers  at  a 
time  when  they  can  ill  afford  to  be  strained.  Cow's  milk 
must  still  form  the  basis  and  most  abundant  article  of 
diet. 

The  cutting  of  teeth  indicates  that  the  chemical  por- 
tion of  the  digestive  process  (5)  has  been  established 
and  that  the  mechanical  function  (5)  is  being  devel- 
oped. The  infant  is  prepared  chemically  to  change 
many  of  the  articles  of  diet  that  the  mother  eats,  but  it 
cannot  yet  prepare  them  so  that  they  will  be  acceptable 
to  the  digestive  tract.  Meat  should  be  finely  divided  be- 
fore being  swallowed,  and  until  a  full  set  of  teeth  is  pro- 
vided for  this  purpose  the  dividing  must  be  done  by  the 
nurse  or  mother. 

The  nutriment  of  vegetable  substances  is  enclosed  in 
cellulose  (10),  which  even  the  mother  cannot  digest 
except  to  a  slight  extent.  Therefore  vegetable  food  for 
infants  must  be  well  cooked  to  burst  open   the  indiges- 


28o  INFANT   FEEDING. 

tible  cells.  For  this  reason  only  tender  vegetables  or 
cereals  should  be  used.  A  clear  idea  of  the  difference 
between  vegetables  in  this  respect  may  be  had  by  tasting 
the  tender  tip  of  boiled  asparagus  and  the  woody  butt  of 
the  stalk.  All  vegetable  substances  for  infants  and  chil- 
dren should  be  cooked  until  they  are  as  tender  as  aspara- 
gus tips. 

Fruits  of  various  kinds  are  early  allowable,  such  as 
orange  juice,  apple  sauce  or  baked  apple  with  the  skin 
removed,  stewed  dried  apples,  and  stewed  prunes  after 
the  pulp  has  been  squeezed  through  a  sieve.  These  arti- 
cles are  not  only  digestible,  but  have  a  favorable  action 
on  the  bowels. 

At  the  end  of  the  first  year  we  may  start  with  one 
soft,  semi-solid  meal  during  the  day,  this  to  take  the  place 
of  one  bottle.  As  the  infant  grows  and  shows  an  ability 
to  digest  this  kind  of  food,  a  second  similar  meal  may  be 
substituted. 

A  thin  pap,  made  by  soaking  stale  bread  crumbs  or 
zwieback  in  hot  water  and  adding  this  to  milk,  affords  a 
good  beginning  for  spoon  food.  A  fresh  egg  (113)  boiled 
for  two  minutes  and  thoroughly  stirred  with  bread  or 
cracker  crumbs  is  likewise  generally  relished.  The 
cereals  cooked  to  a  jelly,  salted,  and  covered  with  milk 
make  a  very  good  meal.  From  a  nutritional  standpoint 
oatmeal  is  to  be  preferred,  but  some  infants  seem  to  ob- 
ject to  its  taste.  If  when  it  is  used  there  is  a  tendency  to 
intestinal  fermentation  or  irritation  of  the  skin,  it  had 
better  not  be  employed.  The  higher  grade  of  rolled  oats 
sold  in  packages  should  be  selected,  as  they  contain  less 
husk,  which  is  irritating  to  the  intestines.     While  ordi- 


DIET   DURING   SECOND    YEAR.  281 

nary  oatmeal  requires  many  hours  of  cooking  (102)  these 
rolled  oats  can  be  thoroughly  cooked  by  half  an  hour's 
boiling  in  a  covered  double  boiler  if  plenty  of  water  is 
used,  so  that  each  particle  of  oat  becomes  soaked  before 
the  boiling  temperature  is  reached. 

Sometimes  an  infant  will  readily  take  one  cereal  while 
rejecting  another,  or  will  tire  of  one  preparation  after  a 
certain  amount  of  use,  and  hence  require  a  change. 
Among  the  better  known  prepared  cereals  that  may  be 
used  are  Quaker  Oats,  Hornby's  Steamed  Cooked  Oat- 
meal, Germea,  Pettijohn's  Breakfast  Food,  Wheatena, 
Whole  Wheat  Gluten,  Pearl  Hominy,  Force,  and  Cook's 
Flaked  Rice.  Analyses  of  these  and  other  cereals  will  be 
found  in  another  place  (page  165).  Oatmeal  is  richest  in 
fat  and  protein ;  gluten  comes  next,  and  wheat,  hominy, 
and  rice  follow  in  respective  order.  It  is  not  too  much 
again  to  mention  the  necessity  of  boiling  these  cereals 
with  plenty  of  water.  No  attention  should  be  paid  to  the 
extravagant  claims  made  for  some  of  the  prepared  foods. 
There  is  very  little  difference  between  any  of  them  of  the 
same  class  in  nutritional  value. 

None  of  the  so-called  "  ready-to-serve  "  breakfast  foods 
should  be  given  to  infants  until  they  have  been  boiled 
fifteen  minutes. 

Meat  broths  (in)  may  be  started  with  the  beginning 
of  the  second  year,  using  preferably  those  made  from 
mutton  or  chicken. 

Between  eighteen  months  and  two  years  the  adminis- 
tration of  small  amounts  of  meat  may  usually  begin; 
scraped  beef  (151),  rare  roast  beef,  broiled  beefsteak, 
roast  lamb,  broiled  mutton  chop,  white  meat  of  chicken, 


282  INFANT   FEEDING. 

and  fresh  fish,  boiled  or  broiled,  may  all  be  employed. 
Meat  must  be  given  rather  sparingly  at  the  beginning 
and  always  finely  minced  (108),  the  amount  depending 
upon  the  outdoor  life  and  exercise  the  child  may  be  get- 
ting. At  about  the  same  period  the  following  vegetables 
may  be  allowed  —  thoroughly  baked  potatoes,  spinach 
passed  through  a  colander,  string  beans,  peas,  asparagus 
tips,  boiled  onions,  and  celery  stewed  in  milk.  All  vege- 
tables must  be  very  thoroughly  cooked  to  a  pulpy  consis- 
tency, in-order  to  soften  and  disintegrate  the  cellulose 
(Fig.  35)  and  thus  render  them  more  digestible. 

Sample  Diet  for  Child  of  One  and  One-Half  to  Two  Years. 

c   Glass  of  milk  ;  cereal ;  a  thin  slice  of  stale  bread  with  butter  or 
'  (       zwieback. 

11  a.m  . .  ....  Glass  of  milk  or  cup  of  meat  broth. 

r  Meats  or  fish — any  mentioned  in  previous  paragraph. 
Potatoes  thoroughly  baked  or  mashed — at  first  once  or   twice 

2  to  3  p.  M \       a  week- 

j   Any  succulent  pulpy  vegetable,  slice  of  bread  and  butter,  and 
one  of  the  milk  puddings. 

(   Stale  bread  and  milk,  or  cereal  and   milk,  or  slice  of  bread  and 

I       glass  of  milk  ;  stewed  fruit. 
Tea  or  coffee  should  never  be  given. 

Such  a  dietary  can  be  maintained  from  the  age  of  two 
to  three  or  four  years.  It  is  naturally  only  suggestive 
and  will  need  modifications  in  individual  cases,  both  as  to 
the  periods  of  time  and  articles  of  diet.  At  the  begin- 
ning, most  little  children  will  require  one  night  feeding, 
and  then  a  bottle  of  plain  or  modified  milk  (139)  can  be 
given  at  10  or  11  p.m. 

Much  judgment  is  often  required  in  starting  the 
young  child  on  a  diet  after  the  bottle  has  been  partly  or 
completely  discarded.     There  is  no  objection  to  giving 


DIET   DURING   SECOND    YEAR.  283 

milk  in  a  bottle  once  or  twice  daily  until  the  child  is 
three  or  four  years  old,  if  it  prefers  this  way  of  taking  it. 
A  bottle  holding  ten  or  twelve  ounces  may  be  used,  and 
the  nipple  will  at  least  insure  its  being  taken  slowly. 
Som:  young  children  will  take  milk  in  this  manner  while 
utterly  refusing  it  when  offered  in  a  cup.  By  using  tact 
in  the  method  of  giving  food  and  employing  some  variety 
in  the  dietary,  the  baby  can  usually  be  nourished  success- 
fully. New  articles  must,  however,  be  started  slowly  and 
gradually;  the  danger  is  in  giving  too  much,  both  in 
quantity  and  variety,  in  the  period  between  babyhood 
and  early  childhood. 


PART    IV. 


CHAPTER    XXIII. 
GROWTH    AND    DEVELOPMENT    OF    INFANTS. 

173.  The  best  gauge  of  good  feeding  and  nutrition  will 
be  a  proper  rate  of  growth  and  development.  While  ab- 
solute rules  cannot  be  given  for  every  case,  there  is  a  nor- 
mal ratio  that,  within  certain  limits,  should  be  attained 
by  the  average  infant.  The  exact  ratio  for  each  individ- 
ual is  governed  by  hereditary  influences  determining  the 
general  framework  of  the  body  at  birth,  as  well  as  by  the 
kind  of  food  available  after  birth.  Some  infants  are  born 
with  very  small  bones,  perhaps  in  this  respect  resembling 
one  or  both  parents.  The  birth  weight  of  such  an  infant, 
as  well  as  that  attained  later,  will  be  less  than  that  of  a 
baby  having  a  large  bony  framework.  Different  races,  as 
well  as  families,  show  considerable  variation  in  this  re- 
spect, within  the  limits  of  health.  Needless  alarm  is 
sometimes  excited  if  the  physician  or  mother  simply  con- 
siders averages  that  are  taken  from  a  different  class  or 
community  that  do  not  apply  particularly  to  the  baby 
under  consideration.  In  every  case,  however,  the  ex- 
tremely rapid  growth  of  the  infant  after  birth  makes  a 
careful  observation  of  all  the  phenomena  connected  there- 
with not  only  interesting  but  important. 

174-  Of  all  the  factors  to  be  thus  considered,  weight  is 
the  most  important.  It  is  practically  the  most  valuable, 
as  showing  whether  the  food  has  the  proper  nutritive  in- 


288  INFANT   FEEDING. 

gradients  and  whether  digestion  and  assimilation  are  well 
performing  their  functions.  From  birth  on,  the  weight 
of  the  body  must  be  taken  and  recorded  at  regular  inter- 
vals, preferably  once  a  week  (128). 

If  food  is  being  changed  to  try  and  correct  a  station- 
ary or  losing  weight,  the  scales  may  be  used  every  two  or 
three  days,  but  it  must  always  be  remembered  that  babies 
are  apt  to  gain  irregularly  at  short  intervals.  One  day 
the  infant  may  show  a  gain  of  an  ounce  and  the  next  day 


Fig.  74. —  Grocer's  Scales  for  Weighing   Infants  and  Children. 

a  quarter  of  that  amount,  while  doing  perfectly  well. 
Again,  the  weight  may  remain  stationary  for  a  day  or  so, 
and  then  jump  up  two  ounces  in  twenty-four  hours.  The 
same  person  should  do  the  weighing  on  the  same  scales, 
to  insure  uniformity.  A  grocer's  scales,  weighing  frac- 
tions of  an  ounce,  or  those  specially  constructed  for  in- 
fants, may  be  used. 

The  following  chart,  devised  by  Carr,  is  convenient  to 
record  the  weighings.  After  weighing,  put  a  dot  where 
the  line  from  the  infant's  weight  crosses  the  line  from  its 


GROWTH   OF   INFANTS. 


289 


age  in  weeks.     By  connecting  the  dots,  the  weignt  line  is 
the  result. 


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The  infant  should,  of  course,  always  be  weighed  in 
the  same  clothing,  that  can  then  be  easily  deducted  from 
the  total. 


J9 


290 


INFANT   FEEDING. 


At  birth  the  male  infant  usually  weighs  a  little  more 
than  the  female.  In  a  series  measured  for  the  author, 
the  males  weighed  from  six  to  eight  pounds,  and  the 
females  from  five  and  a  half  to  seven  pounds.  During 
the  first  two  months,  it  is  considered  by  Rotch  that  the 
daily  average  gain  should  not  fall  below  20  gm.  (two-thirds 
of  an  ounce).  He  gives  the  following  table  indicating  a 
healthy  increase  in  weight : 


Weight. 

Average  Gain  Per 
Day. 

Grams. 

Pounds. 

Grams. 

Ounces. 

At  birth 3,000-4.000     6.6-S.S 

20-30 
I0-20 

The  infant  should  double  its  birth  weight  at  five  or 
six  months,  and  treble  it  at  fifteen  or  sixteen  months. 

175.  The  length  of  the  new-born  baby  is  slightly  greater 
in  the  male  than  in  the  female.  In  a  number  measured 
for  the  author,  the  males  averaged  50  cm.  (19.6  inches), 
and  the  females  48.6  cm.  (19.1  inches). 

Growth  in  length  is  extremely  rapid  during  infancy, 
especially  in  the  earlier  months.  It  is  most  rapid  during 
the  first  month,  a  little  less  so  during  the  second,  the  rate 
of  rapidity  decreasing  with  each  month.  The  following 
figures  referring  to  growth  in  length  are  taken  from 
Rotch : 

The  average  increase  for  the  first  month  is  about  4.5 
cm.  {\}{  inches);  for  the  second  month  about  3.0  cm. 
(ij4  inches);  for  the  third  to  the  fifteenth  month  about 
1  to  1.5  cm.  {Yz  to  ?4  inch);  for  the  first  year  about  20 
cm.  (8  inches);   for  the   second  year  about   9   cm.  (3^ 


GROWTH    OF   INFANTS.  291 

inches);  for  the  third  year  about  7.4  em.  (3  inches);  for 
the  fourth  and  fifth  years  about  6.4  cm.  (2^5  inches) ;  for 
the  fifth  to  the  fourteenth  year  about  6  cm.  (2H  inches). 

176.  One  of  the  best  indices  of  proper  nutrition  is  an 
easy  and  timely  cutting  of  the  first  teeth.  This  process 
starts  early  in  intra-uterine  life  and  should  be  completed 
at  the  end  of  infancy.  At  birth,  although  nothing  but 
smooth  gums  are  to  be  seen,  the  alveolar  processes  enclose 
the  twenty  temporary  or  milk  teeth  in  embryo.  When 
beginning  to  come  through  the  gums,  they  usually  ap- 
pear in  groups.     The  first  to  be  cut  are  apt  to  be  one  or 


Fig.  76. — Diagram  Showing  Average  Months  for  Cutting  Teeth. 

both  of  the  middle  lower  incisors,  at  the  sixth  or  seventh 
month.  The  rest  are  gradually  evolved,  usually  in  the 
following  order:  upper  central  incisors,  upper  lateral  inci- 
sors, four  anterior  molars,  four  canines,  and  finally  the 
four  posterior  molars.  The  first  dentition  should  be 
completed  by  the  end  of  infancy  at  the  age  of  two  and  a 
half  years. 

There  is  always  some  variation,  within  the  limits  of 
health,  as  to  the  exact  time  of  the  evolution  of  the  teeth. 
It  may  be  said,  however,  that  much  delay  in  teething  is 
an  evidence  of  faulty  nutrition  or  constitutional  disease, 
such  as  rickets.     Such  delay  must  hence  call  for  a  care- 


292 


INFANT   FEEDING. 


ful  investigation  of  the  food,  both  as  to  proper  ingredients 
and  adaptability  for  the  infant's  digestion. 


Fig.  77.— One  Day  Old. 


177.  A  few  pictures  of  normally  developing  infants  will 
be  shown,  as  affording  a  guide  to  the  eye  in  recognizing 
what  may  be  expected  at  various  ages.     Care  has  been 


Fig.  78. — Three  Months 


taken  to  get  these  pictures  in  natural  positions  and  post- 
ures.    Just  after  birth,  the  trunk,  arms,  legs,  and  head 


GROWTH    OF   INFANTS. 


293 


have  peculiar  conformations.     The  body  is  of  an  elliptical 
shape,  with  the  widest  part  at  about  the  centre  over  the 


Fig.  79. — Six  Months. 


liver,  in  the  region  of  the  lower  ribs.     The  two  ends  of 
the  ellipse,  represented  by  the  thorax  and  pelvis,  are  small 


Fig.  80.— Six  Months. 


and  not  well  developed.     The  arms  are  stronger  and  bet- 
ter developed  than  the  legs.     During  intra-uterine  life  the 


294 


INFANT   FEEDING. 


baby  is  placed  in  a  sort  of  squatting  position,  with  the 
legs  drawn  up  and  curled  inward.     This  explains  why  the 


'■'"''  &W& 

** '''$&& 

if 

K 

J 

1  1 

■ 

■H- 

Fig.  8i.— Twelve  Months. 


young  infant's  legs  are  not  straight,  but  have  a  decided 
bowing  in  of  the  tibia  and  fibula.     The  soles  of  the  feet 


■a 

it. 

!  ;1^'8        Ml  1  fcfc|         '^^^m*^ 

JMt«^t  j^^:  ^"                                       •'^^WfcpB6*it-JN  _.                     *  3^5^T^^B^.^B 

Fig.  82.— Twelve  Months. 


also  tend  to  face  inward.     The  head  is  larger  than  the 
chest  at  this  time,  with  a  very  short  neck,  and  the  baby 


GROWTH    OF    INFANTS.  295 

assumes  a  position  of  general  flexion.  The  peculiarities 
of  early  infantile  shape  and  position  are  well  shown  in  the 
illustrations. 

For  a  time  after  birth  the  greatest  relative  strength  is 
shown  in  the  hands  and  arms,  as  one  can  easily  verify  by 
allowing  the  infant  to  grasp  a  finger  and  then  trying  to 
pull  it  away.     At  about  three  months  the  muscles  of  the 


Fig.  83. — Fourteen  Months. 

neck  have  developed  sufficiently  to  allow  the  infant  to  try 
and  hold  up  its  head  in  an  uncertain  way.  At  the  sev- 
enth or  eighth  month  the  muscles  of  the  back  have  become 
strengthened  so  that  the  baby  can  sit  up,  and  shortly  after 
this  the  infant  maybe  allowed  to  creep.  There  should  be 
given  free  play  for  the  muscles  of  the  arms  and  legs  from 
the   first,   as  muscular   and   bony   development   is    thus 


296 


INFANT   FEEDING. 


Fig.  84. — Fourteen  Month?. 


Fil..  85. — Eighteen  Months. 


GROWTH    OF  INFANTS. 


297 


riG.  86. — Eighteen  Months. 


298 


INFANT   FEEDING. 


Fig.  88.— Rontgen  Picture  of  an  Infant  at  Nine  Weeks. 

encouraged.  The  bones  of  the  legs  thus  grow  and 
straighten  out,  but  this  will  be  interfered  with  if  the  baby 
is  made  to  sustain  the   weight   of   the   body   too   soon. 


GROWTH    OF    INFANTS.  299 

The  average  baby  should  not  be  encouraged  to  stand 
before  the  twelfth  month ;  efforts  to  walk  may  be  begun 
from  then  on  to  the  fifteenth  and  sixteenth  month. 
When  walking  has  been  established  the  legs  should  be 
straight.  The  chest  develops  rapidly,  with  enlargement 
of  the  pectoral  and  shoulder  muscles,  and  its  circumfer- 
ence usually  equals  that  of  the  head  by  the  end  of  the 
first  year.  The  Rontgen  picture  taken  for  the  author  by 
Dr.  W.  J.  Morton  shows  the  undeveloped  condition  of 
the  bones  of  a  young  infant,  and  the  importance  of  giving 
proper  nutriment  to  build  up  these  and  other  tissues. 


CHAPTER    XXIX 

Methods  and  Results  of  Measuring  Normal  Infants. 

178.  In  order  to  have  additional  and  new  data  relative 
to  the  growth  of  healthy  infants,  a  series  of  careful  meas- 
urements were  made  for  the  author  by  Dr.  A.  Hrdlicka, 
the  anthropologist,  assisted  by  Dr.  Pisek.  Two  hundred 
infants  were  thus  examined,  and  the  tables  and  deduc- 
tions given  below  are  obtained  solely  from  this  work. 
By  having  one  man  alone,  and  he  an  expert,  make  all  the 
measurements  with  instruments  of  precision,  it  is  be- 
lieved that  reliable  statistics  have  been  obtained.  At  the 
same  time  only  a  few  measurements  that  would  throw 
light  upon  the  general  development  of  the  infant  were 
taken,  so  that  any  careful  person  can  make  similar  measure- 
ments for  comparative  purposes.  Healthy  children  from 
the  nurseries  of  the  New  York  Infant  Asylum,  the  New 
York  Foundling  Asylum,  and  the  Mount  Vernon  Infant 
Asylum  were  used,  and  the  author  extends  thanks  to 
these  institutions  for  the  courtesies  extended.  The  ages 
of  the  infants  varied  from  the  new-born  of  a  few  hours  to 
those  of  two  years.  There  were  ninety-six  males  and  one 
hundred  and  four  females.  Well-developed,  children  only 
were  selected,  the  majority  being  on  the  breast  and  the 
remainder  bottle-fed  but  in  every  instance  doing  well  on 
its  feeding.  Any  child  who  had  been  in  hospital  or 
showed  signs  of   marasmus,  rickets,  or    other  constitu- 


METHODS  OF    MEASURING  INFANTS.         301 

tional  disease  was  rejected,  as  the  purpose  was  to  obtain 
the  measurements  of  the  average  healthy  child  at  various 


Fig.  89. — French    Calipers. 

ages.  The  instruments  used  for  this  work  were  a  French 
non-stretchable  tape  for  the  circumferences,  a  pair  of 
French  calipers  for  the  diameters,  and  a  measuring  board 


302 


INFANT    FEEDING. 


to  determine  the  length.  The  board  was  designed  to 
give  true  results  and  obviate  the  inaccuracies  obtained  in 
the  usual  forms  of  apparatus  employed.  In  the  ordinary 
forms  the  pelvis  can  be  tilted,  as  only  one  foot  is  pro- 
vided for  by  the  construction. 

The  measuring  board  here  used  consists  simply  of  a 
plain  board  about  forty  inches  long  by  eleven  inches 
wide,  with  a  firm  upright  headpiece  attached  at  one  end 
and  a  sliding  footboard  at  the  other  end. 

On  the  board  two  engine-ruled  metric  scales  are 
placed  parallel  to  each    other.      Care  must  be  taken  to 


Fig.  go. —Measuring  Board.     A,  Sliding  foot-board;  B,  headpiece  ;  C,  metre  scales. 

have  the  child's  head  well  up  against  the  headpiece  and 
held  there  by  an  assistant,  while  the  measurer  presses 
down  both  knees,  pushing  the  footboard  close  to  the 
plantar  surfaces  of  the  feet.  The  infant  is  then  removed 
and  a  reading  made  on  the  scale. 

The  following  measurements  were  taken: 

Circumference, 
Head   -,  Anteroposterior  diameter, 
Lateral  maximum  diameter. 

Chest — circumference. 


Length  of  body. 
Weight  of  body. 


METHODS    OF   MEASURING  INFANTS.         303 

The  relation  of  the  weight  to  the  length,  the  relation 
of  the  circumference  of  the  head  to  the  length,  and  the 
relation  of  circumference  of  the  chest  to  the  length  were 
then  calculated.  Tables  were  next  prepared  dividing  the 
results  according  to  ages  in  weeks.  The  resume  given 
below  has  been  reduced  to  ages  in  months  for  the  pur- 
pose of  brevity  and  simplicity.  The  largest  and  smallest 
measurement  of  each  group  is  indicated  in  the  metric 
system,  and  in  inches,  and  pounds  and  ounces. 

If  we  study  the  table,  we  find  that  the  males  weigh 
more  than  the  females  throughout  the  period  of  twenty- 
four  months.  In  length  the  males  also  exceed  the  fe- 
males, but  the  difference  is  slight  up  to  the  twelfth  month, 
when  the  males  show  a  greater  divergence.  This  is  well 
shown  in  the  relation  of  weight  to  length  in  the  last  col- 
umn. The  circumference  of  the  head  is  greater  than  the 
circumference  of  the  chest  at  birth,  and  remains  so  up  to 
the  middle  of  the  first  year,  when  they  begin  to  approxi- 
mate in  size ;  at  the  end  of  the  first  year  the  chest  grows 
larger  than  the  head.  The  females,  it  will  be  noticed, 
begin  to  show  greater  circumference  of  chest  to  head  at 
the  tenth  month,  which  remains  so  throughout.  The 
columns  giving  the  relationship  which  exists  between  the 
circumference  of  the  head  and  the  length  of  body,  and 
that  of  the  head  to  the  chest,  will  be  an  aid  in  recog- 
nizing abnormal  cases,  such  as  rickets  or  hydroceph- 
alus. 

The  relations  spoken  of  above  are  obtained  from  the 
measurements  as  follows : 

1.  Weight  to  the  length. 

Multiply  grams  of  weight  by  100  and  divide  by  centi- 


304 


INFANT    FEEDING. 


metres  of  length.     Example:  Weight. 2, 778  gm.  X  100 -f- 
50  cm.  length  =  55.6,  relation  of  weight  to  length. 

2.  Relation  of  circumference  of  head  to  length  of  body. 

Table  of  Measurements   (Males). 


Males. 

Age 

Weight 

Length 

Circ.  of  head 

Circ.  of  chest 

Ratios  of  measurements 

Grains 

Lbs. 
Oz. 

Centi- 
meter 

In. 

meter 
In. 

Centi- 
meter 

In. 

0  ^  S 
>3  £  v 

ill 

%2j. 

2  05 
is     - 

1  day-1  month 

2778      6  15 
to    3912      8    9 

50.           19.6 
55.3         21  8 

35.1      13.8 
38.3      15.1 

32.       12.6 

36.7      14.4 

91.1 
95.8 

65.8 
72.1 

63. 

71.6 

54.9 

76.7 

1-2  months 

3374       7    6 
to    5216      11    7 

52.5  20.7 

59.6  23.5 

36.6      14.4 
39.5      15.5 

35.        13.8 
38.        15. 

95.6 
96.3 

66.1 
71.6 

63.8 
68.3' 

62.2 
87.6 

2-3 

3459       7    9 
to    5528      12   2 

55.9         22. 
60.8        23.9 

38.9      15.3 
41.2       16.2 

34.9      13.7 
41.2      16.2 

89.7 
100. 

67.1 
70.8 

61.7 
69.5 

59.8 
92.4 

3-4        " 

5018     11    0 
to    6804     14  15  ' 

59.1         23.3 
63.1         24.8 

40.2      15.8 
44.         17.3 

37.5      14.8 
42.        16.5 

93.3 
95.5 

64.9 
70.7 

60.4 
69. 

82.1 
107.8 

1-5 

6152     13    8 
to    7201     15  13 

66.2  26. 

66.3  26.1 

41.3      16.3 
42.2      16.6 

41.1  16.3 

43.2  17. 

99.5 
102.4 

62.3 
63.7 

62.1 
65.2 

92.9 
108.S 

5-6 

4990     11    9 
to    7796      17    2 

59.           23. 
68.5        27. 

40.5      16. 
43.9      17.3 

39.9      15.7 
43.3      17. 

98.5 
98.9 

64.1 
69. 

63.2 
67  9 

83.7 
113.8 

G  -  7 

5698     12    8 
to    7995     18    0 

64.8        25.5 
68.7        27. 

43.2  17. 

45.3  17.8 

41.2      16.2 
45.2      17.8 

95.4 
99.8 

65.3 
67.5 

62.6 
68.2 

87.9 
119.1 

7-8        « 

4536       9  15 
to    7924     17    6 

59.1        23.3 

70.8        27.9 

40.        15.7 
44.4      17.5 

38.        15. 
44.9      17.7 

95. 

102. 

62.7 
69.1 

63.4 
64.3 

76.8 
111.9 

8-9 

6804     14  15 
to    8661      19    0 

66.1        26.0 
70.8        27.9 

44.7      17.6 
47.3      18.6 

40.8      16.1 
47.1      18.5 

91.3 

99.6 

63.3 
69.2 

59.!. 
69. 

101.5 
122.3 

9-10 

6662     15    1 
to    8732     19    2 

64.8        25.5 
71.1        28. 

42.9      16.9 
46.3      18.2 

42.3      16.7 
46.1      18.2 

98.6 
99.6 

65.1 
68.3 

64.8. 
66. 

102.5 
122.8 

10-11 

6776     14  14 
to    8565    18  12 

64.7        25.5 
79.           31. 

44.8      17.6 
45.5      17.9 

39.2  15.4 

45.3  17.8 

87.5 
99.6 

63.6 
69.5 

56.3 
68. 

104.7 
119.9 

11  -  12         " 

6634      14    9 
to    8392     18    3 

66.1        26. 
69.8        27.5 

44.7      17.6 
45.3      17.8 

43.4      17.1 
45.1      17.8 

97.1 
99.5 

64.9 
67.3 

64.5 

68.2 

99.4 

120.2 

12-13         " 

7938     17    8 
to    9157     20  .1 

69.4  27.3 

71.5  28.2 

45.6       18. 
47.         18.5 

42.1      16.5 
48.3      19. 

92.3 

102.7 

63.8 
66.6 

60.7 
67.3 

114.4 
1281 

13  - 14        « 

7258     15  15 
to    8874     19    7 

69.6        27.4 
76.           29.9 

46.         18.1 
48.3       19. 

42.1      16.5 
47.7      18.8 

91.5 

98.8 

63.4 
67.7 

60.5 
64.3 

104.3 
121.1 

20-21         ft 

10093     22    2 

75.7        29.8 

48.1      18  9 

50.1      19.7 

104.2 

63.5 

66.2 

133.3 

22-23         ft 

8108     18    5 
to  11113      24  6 

72.2        28.4 
83.4        32.8 

45.         17.7 
47.9       18.9 

43.8      17.2 
51.7      20.4 

97.3 
107.9 

57.4 
62.3 

60.6 
61.9 

112.3 
133.3 

23-24         n 

10886    23  14 
to  11113     24  6 

76.4         30.1 
82.          32.3 

47.6       18.7 
49.         19.3 

50.7  19.9 

50.8  20. 

106.5 
103.7 

59.7 
62.3 

61.9 
66.4 

132.8 
145.5 

2-'3  years 

10830    23  12 

79.8        31.4 

49.         19.3 

49.9      19  6 

101.8 

61.4 

62.5 

135.7 

Multiply  circumference  of  head  by  100  and  divide  by 
length  of  body.     Example:  35.1  X  100  -r-  50  =  70.2. 

3.  Relation  of  circumference  of  chest  to  length  of 
body. 


METHODS    OF   MEASURING   INFANTS. 


305 


Multiply  circumference  of  chest  by  100  and  divide  by 
length  of  body.     Example:  32  X  100  -r-  50  =  64.0. 

4.  Relation  of  circumference  of  head  to  circumference 
of  chest. 

Table  of  Measurements  (Females). 


Females 
Age 

Weight 

Length 

Circ.  of  head 

Circ.  of  chest 

Ratios  of  measurements  '"» 

5 

J   0 

3  I 

6 

ol 

0 

3  a 

a 

Jlf 

(5  J:~ 

~  ~- 

£"! 

1  day-l  month 

2580 
to  3601 

5  10 
7  14 

48.6 
52.8 

19  1 
20.8 

33.4 
37.1 

13.1 
11.6 

30. 
35.9 

11.8 
14.1 

89.8 
96.8 

66.1 
72.2 

61.7 

69.8 

53.1 
71.7 

1-2  months 

3373 
to  4678 

7  6 
10  4 

52. 
59.3 

20.5 
23.3 

35.3 
39. 

13.9 
15.4 

32.8 
39. 

12.9 
15.4 

95.7 
100. 

63.6 
73.2 

61.5 
66.8 

64.9 
78.9 

2-  3 

3799 
to  6010 

8  5 
13  3 

54.6 
62. 

21.5 
24.4 

37.3 
41.1 

14.8 
16.2 

34.8 
39.8 

13.7 
15.7 

93.3 
96.8 

65.8 
70.1 

59.7 
68.9 

67. 
101. 

3-4        " 

4281 
to  5698 

9  C 
12  8 

56.3 
61.9 

22.2 
21.4 

39. 
42.1 

15.4 
16.6 

36.2 

44. 

14.3 
17.3 

92.8 
104.5 

64.2 
72.4 

61.8 
71.7 

75.7    ' 
97.7 

4-5        " 

4494 
to  5585 

9  14 
12  5 

59.9 
62.3 

23.6 
24.5 

40.2 
41.3 

15.8 
16.3 

37.1 
41.7 

14.6 
16.4 

92.3 
100.9 

65.7 

67. 

60.5 
66.9 

75. 
89.6 

5-6 

5500 
to  6549 

12  2 
14  0 

61.9 
66. 1 

24.4 
26. 

41.7 
44.6 

16.4 
17.6 

38.6 
43.2 

15.2 
17. 

92.5 
90.8 

65.3 
67.9 

59. 

66.1 

88.8 
99.7 

0-7 

C634 
to  7768 

14  9 
17  1 

63.9 
66. 

25.2 
26. 

43.1 

43.8 

17. 
17.2 

39.8 
43.1 

15.7 
17. 

92.3 
98.4 

65.6 

67.6 

62.3 
65.4 

103.8 
117.7 

7-8 

6577 
to  S700 

14  7 
19  3 

63.2 
69.9 

24.9 
27.5 

42.7 
44. 

10.8 
17.3 

42.1 
46.8 

10.6 
18.4 

98.6 
106.4 

63. 
68.8 

66.6 
70.7 

101.1 
125.3 

3-9 

7030 

to  7853 

15  7 
17  3 

65.8 
68.8 

25.9 
27.1 

42.1 
46.2 

16.0 
18.2 

41.2 
43.7 

16.2 
17.2 

97.8 
94.6 

63.8 

67.2 

01.1 

66.2 

104.6 
115.5 

9-10        " 

5557 
to  6804 

12  3 
14  15 

62.9 
64.4 

24.8 
25.4 

42.4 
42.8 

16.7 
16.9 

39.3 
40.8 

15.5 
16.1 

92.7 
95.3 

66.5 
67.2 

61. 
64.8 

88.3 
105.6 

10  - 11       " 

5188 
to  9044 

11  6 

19  13 

64.4 
69.8 

25.4 
27.5 

43.6 

45.9 

17.2 

1S.1 

42.5 

48. 

16  7 
19. 

97.4 
104.6 

64.8 
70.8 

63.4 
69.1 

80.0 
129.5 

11-12       " 

0932 

to  9299 

15  3 

20  6 

63.7 
71.3 

25.1 
28.1 

43.7 
46.3 

17.2 
18.2 

42.8 
48.3 

16.9 
19. 

97.9 
104.3 

63.2 
69.2 

62.1 
72.4 

107. 
134.8 

12-13 

6152 
to  8590 

13  8 

18  13 

62.5 

71.1 

25.6 
28. 

41.1 
44. 

16.2 
17.3 

43.1 
48.1 

17. 
18.9 

104.8 
109.3 

61.7 
65.8 

67.7 
68.9 

98.4 
120.8 

13-14 

7655 
to  9526 

16  14 
20  11 

70.5 
72.6 

27.7 

28.6 

45.3 
48.1 

17.8 
18.9 

45.1 

49.4 

17.8 
19. 

99.5 
102.7 

63. 
66.9 

63.7 
70. 

108.6 
131.2 

16-17        " 

7513 
to  8080 

16  8 

17  11 

69.1 
72.4 

27.2 
28.5 

44.7 
45.1 

17.6 
17.8 

45.2 
47.2 

17.8 
18.6 

101.1 
104.6 

61.7 
65.3 

02.4 
68.3 

103.8 
110.9 

17-18        " 

7620 

16  12 

71.4 

28.1 

44.3 

17.4 

43.9 

17.3 

99.1 

62. 

61.1 

106.8 

19-20        " 

8335 

IS  3 

73.9 

29.1 

46.3 

18.2 

46.6 

18.3 

100.7 

62.7 

63.1 

112.8 

23  -  24        " 

8789 

19  4 

77.5 

30.5 

45.6 

18. 

47.1 

18.5 

103.3 

58.8 

60.8 

113.4 

Multiply  circumference  of  head  by  100  and  divide  by 

circumference  of  chest.    Example:  32  X  100  -j-  35.1  =  91. 1. 

While  infants  at  birth  may  vary  widely  in  size,  each 


20 


306 


INFANT   FEEDING 


individual  should  develop  in  proper  proportion,  the  vari- 
ous parts  of  the  body  having  a  symmetrical  relationship 
to  one  another.  These  tables  will  thus  be  found  useful 
in  estimating"  a  divergence  from  the  normal  average  in 
any  given  child.     Thus,  for  example,  we  have  a  male  in- 


LENGTH 


WEIGHT 
LBS.  12  OZ. 


LENGTH 


NEWBORN 


WEIGHT 
15.4  LBS. 


WEIGHT 
18  LBS.  9  OZ. 


12  MOS. 
Fig.  91. — Diagrams  of  Relative  Measurements  Constructed  from  Table. 

fant  of  five  and  a  half  months  that  comes  for  examination 
and  to  have  its  feedings  regulated.  It  is  determined  that 
this  infant  should  not  weigh  less  than  4,990  gm.,  the 
length  should  be  between  59.0  and  68.5  cm.,  the  circum- 
ference of  the  head  should  average  about  42.0  cm.,  the 


METHODS   OF   MEASURING   INFANTS. 


307 


chest  slightly  below  this  figure,  and  the  proportion  of  the 
length  to  the  weight  should  not  fall  below  98.8. 

The  diagrams  (Figs.  91  and  92)  done  in  scale  will  show 
to  the  eye  the  averages  of  the  table  at  various  ages. 


LENGTH 


29.8 


WEIGHT 
22  LBS.  2  OZ. 


LENGTH 


32.0 


WEIGHT 
24  LBS. 


24  MOS. 
Fig.  92. — Diagrams  of  Realative  Measurements  Constructed  from  Table. 


CHAPTER    XXX. 
Growth  of  Head. 

179.  In  the  human  being  the  brain  assumes  overmas- 
tering importance  in  the  scheme  of  evolution,  hence  its 
proper  growth  and  development  assumes  relatively  more 
importance  than  that  of  other  parts  of  the  body.  The 
extremely  rapid  evolution  of  the  brain  during  infancy, 
and  the  fact  that  the  future  efficiency  and  well-being  of  the 
individual  depend  so  largely  upon  its  normal  and  healthy 
growth,  render  a  study  of  the  infantile  head  of  great 
interest.  As  the  skull  is  fairly  representative  of  the 
brain  during  the  years  of  its  first  development,  measure- 
ments taken  during  infancy  are  more  instructive  as  to 
brain  size  and  development  than  those  taken  in  later 
years.  The  skull  changes  considerably  in  its  proportions 
during  the  first  three  years  of  life,  and  then  more  slowly 
up  to  the  end  of  the  seventh  year,  when  it  has  very  nearly 
attained  its  full  size.  Ninety-eight  cases,  from  birth  up 
to  two  years,  were  carefully  measured  by  the  author,  and 
the  results  are  incorporated  in  the  following  table. 

Some  of  these  figures  are  very  slightly  under  similar 
measurements  made  by  Dr.  Hrdlicka  in  his  series  upon 
the  general  growth  of  infants.  This  is  explained  by  the 
fact  that  the  author  made  his  studies  upon  hospital  cases, 
where  the  subcutaneous  tissue  over  the  skull  is  apt  to  be 
somewhat    atrophied.      The    bony  configuration  of  the 


GROWTH    OF    HEAD. 


309 


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g     vo 


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u 


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'sqjuom  xis  pus  aAijj 


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sum     'sqiuom 
anoj      puB      33Jqx 


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UO       U3A3S       lS3SBD 

U33jq3i3    'sqjuoui 

33jq3    0}     3U0     UIOJjJ 


^o  00 


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£     2 


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3io 


INFANT   FEEDING. 


skull,  produced  by  the  growing  brain,  would,  however, 
not  be  affected  by  this  circumstance.  No  distinction  was 
made  between  the  sexes.  The  circumference  was  taken 
by  passing  the  tape  horizontally  around  the  head,  passing 
over  the  glabella  and  a  point  just  above  the  external 
occipital  protuberance.  When  this  is  procured  the  fol- 
lowing data  will  give  a  very  rough  approximation  of  the 
volume:  x  :  circumference  :  :  1350  :  50.  Thus,  if  the 
circumference  is  42  cm.,  the  approximate  volume  will  be 


JBrepsna 


£&&& 


'-La/nScfa. 


/" 


Fig.  93. — Outline  of  the  Skull. 


1 1 34  c.c.  The  naso-occipital  arc  was  measured  from  the 
glabella  to  the  external  occipital  protuberance.  Before 
removing  the  tape,  the  three  arcs  composing  the  naso- 
occipital  were  read  off  —  namely,  the  naso-bregmatic,  the 
bregmato-lambdoid,  and  the  lambdo-occipital  arcs.  These 
points  are  shown  in  the  following  outline  of  a  skull,  and 
are  easily  recognized  in  the  infant. 

The  bregma  and  lambda  were  previously  marked  with 
an   aniline  pencil,  so  that  the  readings  on  the  tape  at 


GROWTH    OF    HEAD.  311 

these  points  could  be  readily  made.  Where  the  anterior 
fontanel  was  open,  a  line  in  continuation  of  the  frontal 
sutures  was  marked.  The  binauricular  arcs  were  meas- 
ured, in  both  cases,  from  the  anterior  rim  of  the  meatus, 
and  passing  the  tape  respectively  over  the  bregma  and 
lambda.  When  the  anterior  fontanel  was  open,  the 
antero-posterior  and  lateral  diameters  were  taken.  The 
cephalic,  or  length-breadth  index,  was  measured  by  cali- 
pers, which  were  applied  at  the  greatest  biparietal  and 
antero-posterior  diameters.  The  formula  for  obtaining 
this  index  is  as  follows:  Length  :  Breadth  :  :  100  :  x.  All 
cephalic  indices  falling  below  78  are  classed  as  dolicho- 
cephalic; from  yS  to  80,  mesocephalic ;  and  above  80, 
brachycephalic.  The  facial  length  was  measured  from 
the  root  of  the  nose  to  the  extremity  of  the  chin,  and,  in 
the  absence  of  the  teeth,  falls  relatively  considerably  be 
low  the  adult.  A  configuration  of  the  skull  in  each  case 
was  taken  by  carefully  applying  a  strip  of  sheet-lead  hori- 
zontally around  it,  just  above  the  ear,  the  free  ends  always 
being  on  the  right  side  for  the  purpose  of  uniformity. 
The  tracing  was  then  put  upon  a  chart  by  running  the 
point  of  a  sharp  pencil  just  inside  the  leac1.  It  is  well  to 
mark  the  centre  of  the  lead  in  front,  so  as  to  be  able  ap- 
proximately to  draw  a  median  line  through  the  configura- 
tion and  thus  detect  asymmetry.  It  is  not  contended 
that  this  is  an  absolutely  accurate  method  of  obtaining  a 
configuration  of  the  skull,  as  the  metal  is  so  yielding  that 
there  is  a  possibility  of  its  springing  somewhat  in  trans- 
ferring it  from  the  skull  to  the  chart.  With  care,  how- 
ever, it  is  fairly  accurate,  and  will  exhibit  the  general 
pushing  out  of  the  soft  skull  by  the  growth  of  the  brain, 


312 


INFANT   FEEDING. 


and  any  form  of  asymmetry  that  is  at  all  marked.     The 
following  configurations,  taken  from  the  list,  are  fairly 

typical  of  the  usual  shaping  of  the 
skull,  in  a  horizontal  plane,  at 
various  ages  during  its  most  rapid 
growth. 

1 80.  The  fetal  skull  is  very 
small,  and  oval  at  an  early  stage, 
as  both  the  sensori-motor  and  in- 
tellectual centres  have  not  yet  be- 
gun to  grow.  The  former  begins 
fig  94.-Fetai  skuii  Between        to  develop  later  in  intra-uterine 

1  hree  and  hour  Months. 

life,  and  the  latter  the  last  of  all. 
This  is  beautifully  shown  in  the  configurations  of  the  two 
fetal  skulls.  The  first  shows  an  oval,  undeveloped  brain, 
while  the  second  exhibits  the  forcing  out  of  the  parietal 
bosses  by  the  rapid  evo- 
lution of  the  sensori- 
motor area  of  the  brain, 
while  the  front  of  the 
skull  appears  station- 
ary, from  the  size  of  the 
configuration.  After 
birth  and  with  increase 
in  the  age  of  the  in- 
fants, there  is  noted  a 
gradual  and  steady 
enlargement  of  the 
great  circumference  of 

the      Skull,     and,        from        Fig.    95.— Fetal   Skull,    Seven    Months,    Showing  the 
.I    •  r       •■  ,■  1  Forcing  Out  of  the  Parietal  Bosses  by  the  Develop- 

tniS,     01       ItS      estimated  ment  of  the  Sensori-motor  Area  of  Brain. 


GROWTH    OF   HEAD. 


313 


volume.  The  naso-occipital  arc  likewise  increases  at 
about  the  same  general  rate  as  the  great  circum- 
ference. In  comparing  the  naso-occipital  arc  with  the 
great  circumference,  there  is    an    increasing  difference 


Fig.  96.' 


Great  circumference,  31  cm. 
Naso-occipital  arc,  22  cm. 
Naso-bregmatic  arc,  9  cm. 
Bregmato-lambdoid  arc,  9  cm. 
Lambdo-occipital  arc,  4  cm. 
Binauricular  arc  (through  bregma),  22  cm. 
Binauricular  arc  (through  lambda),  24  cm. 


Horizontal  Configuration  of   New-Born  Baby    (Female),    Small,  but  Sym- 
metrically Developed. 
Measurements. 

Diameters  of  anterior    fontanel — antero-poste- 

rior,  5.5  cm.  ;  lateral,  5  cm. 
Cephalic  index,  8-10. 
Facial  length,  5  cm. 
Circumference  of  chest,  26.3  cm. 
Length  of  body,  46.5  cm 
Weight  of  body,  5  pounds., 


314 


INFANT   FEEDING. 


as  the  infants  grow  older.  Thus,  in  the  table,  the  differ- 
ence under  one  week  is  12.39  cm->  while  at  two  years  it  is 
14.58  cm.  The  naso-bregmatic  and  bregmato-lambdoid 
arcs  are  very  similar  in  the  series,  but  after  seven  months 
the  former  arc  becomes  slightly  larger  from  the  develop- 
ment of  the  frontal  lobes  of  the  brain.  While  the  parie- 
tal bosses  cover  the  sensory  and,  to  a  certain  extent,  the 
motor  cortical  areas,  the  bones  of  the  forehead  will  indi- 
cate by  their  shape  the  stage  of  development  of  the  fron- 
tal lobes,  the  foundation  of  the  intellectual  portion  of  the 
brain.  Although  no  intellectual  growth  can  be  said  to 
take  place  under  two  years,  there  should  be  an  active 
evolution  of  the  front  of  the  brain,  with  increase  of  the 
perceptions.  The  first  rapid  growth  of  the  brain  after 
birth  is  more  in  bulk  than  in  size  and  complexity  of  the 
convolutions.  Hence  in  early  infancy  the  various  corti- 
cal centres  have  but  a  slight  development  and  function. 
With  proper  evolution,  the  convolutions  grow  and  are 
arranged  in  functional  groups,  which  groups,  by  their 
growth,  alter  and  modify  the  shape  of  the  infantile  skull. 
If  the  skull  is  small  or  improperly  shaped  in  any  part,  the 
brain  in  such  an  area  is  imperfectly  developing.  A  cer- 
tain amount  of  asymmetry,  however,  is  found  in  all  skulls, 
as  in  the  other  members  of  the  body,  and  will  be  seen  in 
the  tracings  previously  shown.  Older  children  some- 
times exhibit  a  compensatory  deformity  from  a  too  early 
closure  of  some  of  the  sutures  of  the  infantile  skull,  that 
does  not  allow  the  expanding  brain  to  develop  in  a  sym- 
metrical manner.  Such  cases  are  not  apt  to  exhibit  ab- 
normality of  brain  function.  The  brain  has  simply  pushed 
out  at  the  point  of  least  resistance. 


GROWTH    OF    HEAD. 


3i5 


Fig.  97.— Horizontal  Configuration  of  Baby  of  Ten  Months  (Female).     Fed  on  breast. 
Measurements. 

Great  circumference,  44  cm.  Diameters    of    anterior      fontanel— antero-posterior, 

Naso-occipital  arc,  29  cm.  cm.  ;  lateral,  1  cm. 

Naso-bregmatic  arc,  11. 5  cm.  Cephalic  index,   n-rs. 

Bregmato-lambdoid  arc,  12.5  cm.  Facial  length,  6  cm. 

Lambdo  occipital  arc,  5  cm.  Circumference  of  chest,  43.5  cm. 

Binauricular   arc    (through  bregma),  26  cm.  Length  of  body,  68  cm. 

Binauricular  arc  (through  lambda),  26.5  cm.  Weight  of  body,  14  lbs.  13  oz. 


316  INFANT    FEEDING. 

181.  The  fontanel  is  usually  completely  closed  from 
the  eighteenth  to  the  twentieth  month.  As  will  be  seen 
from  the  table,  the  closing"  is  rather  slow  until  the  twelfth 
month,  when  it  proceeds  much  more  rapidly.  In  all  the 
cases  examined,  the  fontanel  had  closed  by  the  eigh- 
teenth month.  Where  the  fontanel  remains  widely 
open  with  the  increased  age  of  the  infant,  there  will 
always  be  marked  symptoms  of  rickets  elsewhere.  Thus, 
in  the  case  o'f  a  male  infant,  aged  ten  months,  with  both 
diameters  5  cm.,  the  configuration  showed  a  markedly 
rickety  head,  and  the  notes  gave  other  symptoms  of  the 
disease. 

The  facial  length  increases  slowly  in  infants, as  would  be 
expected  from  the  absence  of  teeth.  In  older  babies,  when 
dentition  is  completed,  the  length  increases  more  rapidly. 

The  importance  of  good  nutrition  in  relation  to  brain 
growth  will  be  appreciated  from  the  fact  that,  in  the  cases 
•examined  by  the  author,  the  skulls  of  breast-fed  babies 
presented  slightly  larger  measurements  than  those  artifi- 
cially fed,  especially  when  the  latter  were  not  digesting 
and  assimilating  their  food  well. 

The  principle  of  biology,  that  the  development  of  the 
individual  reproduces,  on  a  small  scale,  the  development 
of  the  race,  is  well  shown  in  the  infant's  brain.  The 
higher  centres  and  the  centres  of  association  are  devel- 
oped late  in  the  child.  These  are  likewise  the  last  ac- 
quirements of  the  race.  The  lower  and  more  funda-= 
mental  animal  traits  are  transmitted  by  inheritance  more 
than  the  higher  ones.  Good  nutrition  and  good  training 
are  both  required  to  develop  the  higher  functions  of  the 
brain  in  a  satisfactory  manner. 


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Food  and  Food  Adulterants  (Preserved  Meats).  Bull.  13,  Pt.  10,  Div. 
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Cereal  Breakfast  Foods.     Bull.  55,  Maine  Agr.  Exp.  Station. 

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Value  of  Potatoes  as  Food.  C.  F.  Langworthy.  U.  S.  Dept.  Agr.  Year 
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Testing  Cows  at  the  Farm.     Wis.  Exp.  Station  Bull.  75. 
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Effect   of   Unequal   Intervals    between   Milkings.     Delaware   Agr.    Exp. 

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Variations  in  Milk  of  Individual  Cows.    Illinois  Agr.  Exp.  Station  Bull.  24. 
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Dairy  Development  in  the  United  States.     H.  E.  Alvord.     Sixteenth  An. 

Report  Bureau  of  Animal  Industry,  U.  S.  D.  A. 
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Dept.  Agr.  Year  Book.  1900. 

Milk:  Its  Nature  and  Composition.     C.   M.   Aikman.     London,  1S99. 
Milk  and  its  Products.     H.  H.  Wing.     New  York.  1S97. 
Dairy  Chemistry.     H.  D.  Richmond.     Philadelphia,  1S99. 


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Testing  Milk  and  Its  Products.     E.  H.  Farrington  and  F.  W.  Woll.     Mad- 
ison, Wis.,  1900. 
Analysis  of  Milk  and  Milk  Products.     Henry  Leffman  and  William  Beam. 
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Methods  of  Analysis  of  the  Association  of  Official  Agricultural  Chemists, 
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Provisional  Methods  for  the  Analysis  of  Foods  Adopted  by  the  Associa- 
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A  Comparison  of  Reagents  for  Milk  Proteids  with  some  notes  on  the 
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Estimation  of  the  Total  Solids  in  Milk  from  the  per  cent  of  Fat  and  the 
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Effect  of  Lime  on  Milk.     Farmers'  Bull.  69  U.   S.   D.  Agr. 

Effect  of  Separator  on  Removing  Dirt  and  Bacteria  from  Milk.  S.  M. 
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Creaming  Experiments.  S.  M.  Babcock.  Eighth  Report  Wisconsin  Agr. 
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Pasteurization  of  Milk  and  Cream  at  140'  F.  E.  H.  Farrington  and 
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Analyses  of  Milk  and  Whey.  L.  L.  Van  Slyke.  New  York  Agr.  Exp. 
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Agricultural  Bacteriology.     H.  W.  Conn.     Philadelphia,  1901. 

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The  Ripening  of  Cream.  H.  W.  Conn  and  W.  M.  Esten.  Storr's  Agr. 
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Boston  Medical  and  Surgical  Journal,  June  26th  and  July  3d,  1902. 
A  Plea  for  the  Conservation  of  Breast   Milk  in  Whole  or  in  Part.     T.  S. 

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Southworth.     Medical  Record,  April  26th,  1902. 
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INDEX. 


Absorption  of  food,  34 
Acidity  of  milk,  66,  135 
Albumin,  12,  39 

in  milk,  48,  51,  71 
Albuminoid,  25 
Albumoses,  32 

in  milk,  52,  71 
Animal  cell,  10 

Babcock  milk  test,  127 
Baby  food  warmer,  251 
Bacteria,  81 

classification  of,  82 

counting,  in  milk,  92,  158-160 

decomposition,  85,  150 

differentiation  of  types  of,  148 

food  of,  83 

in  dust,  87,  95 

in  manure,  86 

in  milk,  80,  in 

in  soil,  86 

lactic,  82,  149,  272 

numbers  of,   in  certified   milk, 
112 

numbers   of,   in   grocery  milk, 
114 

numbers  of,  in  milk,  in 

on  cow's  body,  89 

peptonizing,  85 

poisons  produced  by,  85,  150 

rate  of  growth  of,  83,  91,  92 
Bacteriological       examination       of 
milk,  80,  140,  272 

examination  of  milk,  value  of, 
144 
Bacteriology  of  milk,  80    140 
Barley,  163,  174 
21 


Barley  gruel,  229 

gruel,  dextrinized,  229 
Beans,  165 
Beef  extract,  177 

juice,   176,  243 

pulp,  175,  243 

scraped,   175,  243 

tea,  178,  243 
Biscuits,  analyses  of,  170 
Bottle  brush,  252 

filler,  108 

sterilizer,  113 
Bottled  milk,  108,  215       -    .. 

milk,  advantages  of,  215 
Bowel  washing,  277 
Bread,  168-170 

changes  of  flour  in  making,  168 

Graham,  169 

temperature  of  baking,  170 

whole  wheat,  169 
Breakfast  foods,  165 
Breast,  care  of,  187 

feeding,  187 

feeding,  contraindications   for, 
191 

pump,  192 

shield,  191 
Broths,  chicken,  mutton,   and  veal, 
179.  244 

Calipers,  301 
Calorie,  200 
Cane  sugar,  26,  232 
Carbohydrates,  26 

as  fuel,  39,  200 

effect   on  -proteid   metabolism, 
33-  39 


322 


INDEX. 


Carbohydrates,  estimation  of,  27 
Casein,  12,  43,  44 

to  albumin,  ratio  of,  in  milk,  6S 
Caseinogen,  4S 
.Cellulose,  14,  26,  30,  162 
'Cereals,  162 

analyses  of,  165 

cooking  of,  163,  166 
Cereo,  225 
Certified  milk,  105 

milk,  bacteria  in,  112 

milk,  cost  of  producing,  113 
Clarified  milk,  99 
Colic,    254 
Colostrum,  59,  203.  204 

function  of,  205 
Condensed    milk,    77,   79,    172,  226, 

256 
Constipation,  265 
Cooler,  milk,  no 
Crackers,  analyses  of,  170 
Cream,  71 

albuminoid,  77,  97 

and  milk  mixtures,  213 

centrifugal,  73 

centrifugal,   separation  of  pro- 
teids  in,  76 

difference  between  centrifugal 
and  gravity,  75 

evaporated,   77 

gravity,  72,  2t6 

gravity,  composition  of,  216 

separating,  71 

separator,  74 

thickeners,  76 

time  required  for,  to  rise,  72,  220 
Creamery,  107 
Curd  test,  272 

Decay,  85 

Decomposition,  85,  150 
-Development  of  infants,  2S7 
Dextrin,  32,  35,  167,  224 
Dextrinized  gruels,  224,  229 

gruels,   advantage   of,  as   dilu- 
ents, 224 


Dextrinized  gruels  with  eggs,  242 
Diarrhoea,  summer,  270 
Diarrhoeal   diseases  and  milk  sup- 
ply, 143,  270 
Diastase,  167,  224 
Diet,  balanced,  40 

during  second  year,  279 

of  nursing  mother,  189 

selection  of,  198 
Digestion,  chemical  process  of,  29 

energy  or   labor  expended    in, 

34 

how  human,   differs   from  that 
of  lower  animals,  31 

in  different  animals,  29 

mechanical  process  of,  17 

object  of,  16 

tests,  2S 
Digestive  juices,  33 

juices,  secretion  of,  33 

tract,  development  of,  by  milk, 
22,  24,  50,  203,  212,  246 

tract,  human,  23 

tract  of  cow,  19 

tract  of  dog,  iS 

tract  of  horse,  21 
Diluents,  223,  229 
Diphtheria  and  milk  supply,  142 
Dipper  for  removing  top  milk,  228 
Drugs  eliminated  in  milk,  190 
Dust,  bacterial  spores  in,  95 

Eggs,  13,  1S0 

candled,  183 

composition  of,  iSr 

flavor  of.  182 

market  grades  of,  1S2 

preservation  of,  1S3 
Egg-water,  242 

and  dextrinized  gruel,  242 
Enzymes,  31 

act  by  contact,  33 

in  milk,  52 

of  translocation,  35 
Evaporated  creams,  78 
Excretion,  36 


INDEX. 


323 


Excretion  by  kidneys,  36,  276 

by  lungs,  36,  277 
Extract  of  beef,  178 
Extractives,  13,  177,  278 

Fats,  26 

as  fuel,  36,  200 

as  proteid  sparers,  39 

effect   on   appetite   and    diges- 
tion, 32,  34,  257 

estimation  of,  27 

globules  in  milk,  63 

metabolism  of,  36 
Fecal  matter,  41,  247 

matter,  a  secretion,  41 

matter,    character   of,   depends 
on  food,  41 

matter,  color  of,  42 
Feeding,  adult,  200 

infant,   198 

infant,  according  to  stools,  246, 

254 

infant,  artificial,  246 

infant,  breast,  1S7 

infant,  by  gavage,  258 

infant,  general  rules  for,  257 

infant,  hours  for,  188 

infant,  mixed,  194,  246 

infant,  nasal,  25S 

infant,  percentage,   method  of, 
210,  221,  235 

infant,  premature,  262 

infant,  rectal,  260 

infant,  regularity  necessary  in, 
188 
Fibrin,  39 
Filtered  milk,  99 
Flour,  baked,  16S 

ball,  167 

ball,  changes  in,  16S 
Fontanel,  309,  316 
Food,  classification  of,  25 

function  of,  36 

infant,  administration  of,  251 

infant,  condensed  milk  as,  226, 
256 


Food,  infant,  cream  and  milk  mix- 
tures as,  213 
infant,  effect  of  low  protein  in, 

210 
infant,  for  temporary  use,  241 
infant,    pasteurization   of,    232, 

234,  252 
infant,   percentage  composition 

of,  235 
infant,  preparation  of,  227 
infant,  proprietary,  171 
infant,    selection   of,    198,   -207, 

246 
infant,  sterilization  of.  233 
infant,  top   milk   mixtures   as, 

231 
infant,  warming  of,  251 
infant,  whey   and   cream    mix- 
tures as,  239 
methods  of  selecting  for  adults, 

198 
methods  of  selecting  for  adults 
not     applicable     to     infants, 
198 
of  different  animals,  16,  31 
Formaldehyde  in  milk,  97,  99 
Fruit  tablets,  268 

Gastric  juice,  action  on  meat,  32, 
176 

juice,  secretion  of,  33,  34 
Gelatin,  39,  180 
Globulins,  12 
Glucose,  26 
Gluten,  14,  165,  169 
Glycogen,  13,  35,  38 
Growth,  a  process  of  cell  division, 
11 

of  infants,  287 

of  infant' s  head,  308 
Gruels,  224 

dextrinized,  224,  229 

dextrinized,  advantages   of,  as 
diluents,  224 

Hominy,  analysis  of,  165 


324 


INDEX. 


Ice  in  Chicago,  101 

in  London,  101 

in  New  York,  101 

in  Paris,  101 
Infant  foods  and  feeding,  see  Foods 
and  Feeding. 

rudiment  of  parent,  15 

Junket,  20 

tablets,  67,  241 

Lactalbumin,  45 
Lactometer,  132 
Lecithin,  13,  51,  61,  212 

Legal  standards  for  milk,  134 
Lime,  effect  on  milk,  76,  223 

syrup  of,  235 

water,  136,  223,  234 

Maltose,  32,  35,  167 
Massage  of  bowel,  26a 
Measurements  of  infants,  300,  304, 

305.  307 
Measuring  board,  302 
Meat  bases,  13,  179 

broths,  179,  244 

extracts,  177 
Meats,   175 
Meconium,  41 
Metabolism,  36 

in  adults,  36 

in  infants,  38 

in  starvation,  38 

of  carbohydrates,  36 

of  fats,  36 

of  proteids,  36 
Milk,  acidity  of,  66,  135 

acidity  of,  detection  by  pepsin, 
66 

analyses  of,  47,  49.  64,  69 

analysis  of,  45 

ass',  22,  47,  264 

at  Paris  Exposition  in  1900,  102 

average,  47 

bacteriology  of,  80 

bottled,  io3,  215 


Milk,  certified,  105 

certified,  bacteria  in.  112 

certified,  bacterial  standard  for, 
125 

certified,  cost  of  producing.  113 

clarified,  99 

classification   of,    according    to 
curding  properties,  4S 

commissions,  105 

commissions,  regulations,  118 

comparison  of,  49 

condensed,  74,  79,  172,  226,  256 

cow's,  22,  47,  53,  59 

curding  of,  object  of,  20 

difference    between    acid     and 
rennet  curds  of,  48,  66 

enzymes  in,  52 

fat  of,  45 

filtered,  99 

fresh  cow's,  not  truly  acid,  66 

goat's,  22,  47,  53 

grocery,  106,  114 

grocery,  bacteria  in,  114 

grocery,  cost  of  producing,  115 

inspected,  122 

inspected,  bacteria  in,  125 

laboratories,  244 

lecithin  in,  51 

legal  standards  for,  134 

mare's,  22,  47,  53 

market,  104 

methods  of  testing,  127 

microscopic  appearance  of,  73 

mixed,  of  several  cows,  63 

mixed,  of  several  cows,  analy- 
ses of,  69 

of  different  animals,  47,  49 

one  cow's,  61 

one   cow's,    effect   of  irregular 
hours  of  milking,  65 

one  cow's  fractional  milkings, 
62 

one  cow's,  variations  in,  64 

pasteurized,  95,  100,  233 

peptonized,  147 

physiological  function  of,  22,  24 


INDEX. 


325 


Milk,  preservation  of,  94 

preservation  of  samples,  139 

preservatives,  96,  138 

production  in  Europe,  102 

proteids  of,  43,  53,  71 

receiving  stations,  107 

sheep's,  22,  47,  53 

souring  of,  84 

specific  gravity  of,  130 

sterilized,  94 

sterilized,  detection  of,  139 

sugar  of,  44 

top,  217,  220,  22S 

woman's,  22,  47,  53 

woman's,  examination  of,  194 

woman's,  modification  of,  194 

woman2  s,  ratio   of   fat   to   pro- 
teids in,  214 
Mineral  matter  in  food,  25,  27 

matter  in  milk,  46,  61 

matter,  estimation  of,  46 

Nipple,  251,  253 

care  of.  187 

shield,  191 
Nitrogenous  equilibrium,  37 
Nucleo-albumin,  12 
Nursery  stove,  253 
Nursing,  187 

contraindications  for,  191 

hours  for,  188,  252 

wet,  192 
Nursing-bottles,  232 
Nutritive  ratio,  201 

Oatmeal,  165 
gruel,  229 
gruel,  dextrinized,  229 

Pasteurization  of  milk,  94,  100,  234 
of  milk  in  Europe,  96,  100,  103 

Peas,  165 

Peptones,  32 

in  milk,  52,  71 

Peptonized  milk,  242 

Percentage  feeding,  210,  222,  235 


Premature  infants,  262 
Preservatives,  food,  96 

in  milk,  138 
Proteid,  25 
Protein,  12,  25 

all  animals  must  have,  16 

animals  cannot  elaborate,  15 

decomposition  of,  85 

effect  of  diet,  high  and  low  in, 
210 

estimation  of,  27 

forms  of,  12,  39 

forms  of,  in  milk,  43,  51,  53,  71 

kind  of,  required  in  food,  39 

metabolism  of,  36 

metabolism  of,  effect  of  carbo- 
hydrates on,  3S 

plants  can  elaborate,  15 

quantity  of,  required  in  food, 
40 

vegetable,  14,  162 
Prunes,  267 
Putrefaction,  85 

Rennet,  20 

function  of,  20,  49 
Rice,  165 

gruels,  229 
mould,  167 
Rumen,  18 

Scales,  grocer's,  288 

Scarlet  fever  and  milk  supply,  142 

Separator,  cream,  74 

Skull  outline  of  infants,    310,  312. 

313 
Slime  separator,  25 
Slimy  milk,  86 

Sloane  Maternity  milk  set,  236 
Starch,  26,  163 

bursting  of  grains  by  cooking, 
166 

in  bread,  168 
Starvation,  37 

in  children,  3S 

effect  of  albumen  in,  39 


326 


INDEX. 


Starvation,  effect  of  carbohydrates 
in,  3S 

effect  of  proteid  in,  39 
Sterilization  of  milk,  94,  234 
Sterilizers,  113,  234 
Stomach,  capacity  of  infant's,  250 

of  different  animals,  16-24 

tube,  259 

washing,  259 
Stools,  infants',  41,  247 
vStreptoccoci  in  milk,  S7,  151 
Sugar,  26 

cane,  26,  232 

effect  on  digestion,  34,  257 

estimation  of,  47 

milk,  26,  44,  232 

milk,  of  cows  not  identical  with 
human,  44 
Summer  diarrhoea,  270 

diarrhoea  and  milk  supply,  143, 
271 
Suppositories,  26S,  269 

Teething,  291 
Thickeners,  cream,  76 
Tin  pudding  bag,  167 
Top  milk,  217-220,  22S 
milk  mixtures,  227 
Tuberculin  test,  Sg 


Tuberculosis  and  milk  supply,  86, 

140 
Tuberculous  udder,  SS 
Typhoid  fever  and  milk  supply,  141 

Udder,  cow's,  86 

tuberculous,  SS 
Urea,  36,  276 
Uric  acid,  36 
Urine,  36,  40,  276 
Utensils,  seams  of  dairy,  90 

Vegetable  foods,  162 
Viscogen,  76 
Vomiting,  254 

Weaning,  194 
Weight  chart,  289 

infant,  2S9 
Wet-nursing,  192 
Wheat  bread,  170 

breakfast  foods,  165 

flour,  172 

flour  gruels,  229 

flour  gruels,  dextrinized,  229 
Whey,  49,  65,  69,  241 

analyses  of,  69 

and  cream  mixtures,  239 

to  make,  241 

food  value  of,  241 


